ALBERT

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Muhammad Abid, Muhammad Sajid Khan, Tahir Abdul Hussain Ratlamwala〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Parabolic dish solar collector system has capability to gain higher efficiency by converting solar radiations to thermal heat due to its higher concentration ratio. This paper examines the exergo-economic analysis, net work and hydrogen production rate by integrating the parabolic dish solar collector with two high temperature supercritical carbon dioxide (s-CO〈sub〉2〈/sub〉) recompression Brayton cycles. Pressurized water (H〈sub〉2〈/sub〉O) is used as a working fluid in the solar collector loop. The various input parameters (direct normal irradiance, ambient temperature, inlet temperature, turbine inlet temperature and minimum cycle temperature) are varied to analyze the effect on net power output, hydrogen production rate, integrated system energetic and exergetic efficiencies. The simulations has been carried out using engineering equation solver (EES). The outputs demonstrate that the net power output of the integrated reheat recompression s-CO〈sub〉2〈/sub〉 Brayton system is 3177 kW, whereas, without reheat integrated system has almost 1800 kW net work output. The overall energetic and exergetic efficiencies of former system is 30.37% and 32.7%, respectively and almost 11.6% higher than the later system. The hydrogen production rate of the solarized reheat and without reheat integrated systems is 0.0125 g/sec and 0.007 g/sec, accordingly and it increases with rise in direct normal irradiance and ambient temperature. The receiver has the highest exergy destruction rate (nearly 44%) among the system components. The levelized electricity cost (LEC) of 0.2831 $/kWh with payback period of 9.5 years has proved the economic feasibility of the system design. The increase in plant life from 10 to 32 years with 8% interest rate will decrease the LEC from (0.434-0.266) $/kWh. Recuperators have more potential for improvement and their cost rate of exergy is higher as compared to the other components.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Yuan Xue, Shixiong Min, Fang Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although black phosphorous (BP) and its derived materials have shown great potential for application in photocatalytic H〈sub〉2〈/sub〉 evolution reaction (HER), their HER activity and stability still remains unsatisfied mainly due to the insufficient charge separation, the lack of surface active sites, and the defect-riched nature of BP. Herein, we report that BP nanosheets decorated with in situ grown Pt (BP NSs/Pt) could act as a highly efficient catalyst for photocatalytic H〈sub〉2〈/sub〉 evolution in an Erythrosin B (ErB)-sensitized system under visible light irradiation (≥450 nm) in the presence of triethanolamine (TEOA) as sacrificial electron donor. It is found that BP NSs can provide large surface area for the confined growth of Pt nanoparticles with a high dispersion and a reduced size but also stabilize the loaded Pt nanoparticles by covalent bonds at the BP NSs/Pt interfaces. Moreover, BP NSs offer a fast electron transfer pathway to facilitate the photocatalytic HER over in situ grown Pt catalyst. As a result, BP NSs/Pt catalyst exhibits ∼6 times higher H〈sub〉2〈/sub〉 evolution activity than free Pt nanoparticles and an apparent quantum yield (AQY) of 0.57% at 500 nm irradiation in ErB-TEOA system. This work indicates the potential of BP NSs as an effective 2D matrix to construct numerous high performance photocatalysts and photocatalytic systems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): C. Juillet, M. Tupin, F. Martin, Q. Auzoux, C. Berthinier, F. Miserque, F. Gaudier〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Under Pressurized Water Reactor normal operating conditions, the external surface of zirconium alloys cladding absorbs a fraction of the hydrogen produced by water reduction. During spent fuel transport, hydrogen may desorb from the cladding. The study aims to identify and quantify the rate-limiting step in the hydrogen desorption process initially present in the alloy. To better understand this process, the Thermal Desorption Spectrometry (TDS) was used in association with X-ray Photoelectron Spectroscopy analysis. TDS results were analysed with finite elements simulations using the Cast3M code. The optimization of the kinetic constants of hydrogen desorption was performed with CEA (Alternative Energies and Atomic Energy Commission)-tool URANIE. Results showed that hydrogen desorption kinetics from the metal is limited by the surface molecular recombination. Arrhenius-type temperature dependence of kinetic constants allowed to simulate experimental data with a good agreement. The optimized activation energy and the pre-exponential factor for desorption processes were in the range of 290 ± 10 kJ mol〈sup〉−1〈/sup〉 and 3 × 10〈sup〉7〈/sup〉 m〈sup〉4〈/sup〉 mol〈sup〉−1〈/sup〉 s〈sup〉−1〈/sup〉 respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Abhishek Rajput, Prem P. Sharma, Vikrant Yadav, Vaibhav Kulshrestha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Proton exchange membrane is a basic element for any redox flow battery. Nafion is the only commercial available proton exchange membrane used in different electro-chemical energy systems. High cost restrict it's used for energy generation devices. In present work, we synthesised styrene divinylbenzene based composite proton exchange membranes (PEMs) with varying sulfonated graphene oxide (sGO) content for redox flow battery (RFB). Synthesized copolymer PEMs were analyzed in terms of their chemical structure with the help of FT-IR spectroscopy to confirm desired functional groups at appropriate position. Electrochemical characterization was performed in terms proton-exchange capacity, protonic conductivity and water uptake. Membrane shows adequate proton exchange capacity with good proton conductivity. Vanadium ion permeability was also tested for the prepared membrane to assess capability for vanadium redox flow battery (VRFB) in contrast with commercially available Nafion 117 PEM. Higher VO〈sup〉+2〈/sup〉 ion cross-over resistance was found for CEM-4 with 7.17 × 10〈sup〉−7〈/sup〉 cm〈sup〉2〈/sup〉 min〈sup〉−1〈/sup〉 permeability, which is about half of the CEM-1. Further CEM-4 was also evaluated for charging-discharging phenomenon for single cell VRFB. The values of columbic, voltage and energy efficiency for VRFB confirms prepared membrane as a good candidate for redox flow battery. Composite PEM also shows better mechanical and thermal stability. Results indicates that synthesized composite membrane can be used in vanadium redox flow battery.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323584-fx1.jpg" width="395" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 26 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 36〈/p〉 〈p〉Author(s): Zhiguo Liu, Xiao Zhang, Zhixiang Jiang, Hsueh-Shih Chen, Ping Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Non-metal doping not only optimizes the energy band structure of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 to improve the absorption of visible light, but also exacerbates the distortion of lowest and highest unoccupied molecular orbital plane, causing polarization, thereby improving photocatalytic activity. For the first time, S and P are co-introduced into g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 network to enhance photocatalytic performance and create various tubular morphologies. The ratio of S to P is crucial to control the tubular morphology and property. In the photocatalytic process, the separation of electrons and holes causes by the polarization of the S and P elements and the synergy of the tubular morphology results in new migration paths for photogenerated electrons and holes. Using optimized preparation conditions, g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 tubes co-doped with S and P (CNSP) reveal very high H〈sub〉2〈/sub〉 generation efficiency (163.27 μmol/h), which is two orders of magnitude higher compared to that of pure g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and apparent quantum yield is 18.93% at 420 nm. Fast degradation of Rhodamine B by using CNSP occurs within 5 min under visible light irradiation. Because of the reproducible process, the synthetic strategy provides a novel method for controlling the morphology of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉-based materials with super activity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919322487-fx1.jpg" width="311" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Shuguo Qu, Minhui Li, Chenchen Zhang, Jihai Duan, Weiwen Wang, Jianlong Li, Xiaojin Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel proton exchange membrane was synthesized by embedding a crystalline which was nano-assembled through trimesic acid and melamine (TMA·M) into the matrix of the sulfonated poly (ether ether ketone) (SPEEK) to enhance the proton conductivity of the SPEEK membrane. Fourier transform infrared indicated that hydrogen bonds existed between SPEEK and TMA·M. XRD and SEM indicated that TMA·M was uniformly distributed within the matrix of SPEEK, and no phase separation occurred. Thermogravimetric analysis showed that this membrane could be applied as high temperature proton exchange membrane until 250 °C. The dimensional stability and mechanical properties of the composite membranes showed that the performance of the composite membranes is superior to that of the pristine SPEEK. Since TMA·M had a highly ordered nanostructure, and contained lots of hydrogen bonds and water molecules, the proton conductivity of the SPEEK/TMA·M-20% reached 0.00513 S cm〈sup〉−1〈/sup〉 at 25 °C and relative humidity 100%, which was 3 times more than the pristine SPEEK membrane, and achieved 0.00994 S cm〈sup〉−1〈/sup〉 at 120 °C.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Ying Han, Weirong Chen, Qi Li, Hanqing Yang, Firuz Zare, Yongkang Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the fast development of DC Microgrid (MG) technology, its operating economy and reliability are getting more and more concern. The traditional distributed control method is aimed at power balance and system stability, and is difficult to meet the requirement of energy management system for multi-source hybrid DC MG. This paper provides a two-level energy management strategy for PV-fuel cell-battery-based DC MG, which is divided into device control level and system control level. At the device control level, the distributed control methods based on MPPT-droop dual-mode control and droop control are proposed to enhance system reliability; at the system control level, the equivalent consumption minimization strategy (ECMS) is used to distribute system net power between battery pack and fuel cell system. A lab-scale DC microgrid platform is developed to verify the proposed energy management strategy in this paper. Moreover, the analysis and compare of the results show that the proposed two-level energy management strategy can achieve lower equivalent hydrogen consumption than classical PI control and state machine control method.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Nicolás Cobos Ullvius, Masoud Rokni〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While energy demand in this fast developing world is increasing, its future is being compromised by the CO〈sub〉2〈/sub〉 emissions produced through the burning of fossil fuels. Clean energy technologies are available, but there are still barriers hindering their full integration into the society, the majority of which are economic and social. For these reasons, the development of new technologies and configurations to make renewable energies systems more cost-effective is urgently needed. The plant design proposed in this paper consists of basic Dish-Stirling collectors supported by a reversible solid oxide fuel cell acting as a power generator and storage unit, and therefore offering dispatchable power on demand. Further, the system reuses the waste heat for seawater desalination, which is very convenient for arid areas with high solar radiation and shortage of freshwater. The present work is an analytical study in which thermodynamic investigation of the performance evaluation of a self-sustainable polygeneration system with integrated hydrogen production, power generation, and freshwater production is conducted. An evaluation in a real context (South Africa) showed the potential of this system to supply 500 kW, 24 h a day, while producing a considerable amount of freshwater. Although the distillation system presented is able to produce 8464 L per day, there is potential for it to increase its output by nine times or more.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Hongri Wan, Xiaofang Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nitrogen/sulfur co-doped disordered porous biocarbon was facilely synthesized and applied as anode materials for lithium/sodium ion batteries. Benefiting from high nitrogen (3.38 wt%) and sulfur (9.75 wt%) doping, NS〈sub〉1-1〈/sub〉 as anode materials showed a high reversible capacity of 1010.4 mA h g〈sup〉−1〈/sup〉 at 0.1 A g〈sup〉−1〈/sup〉 in lithium ion batteries. In addition, it also exhibited excellent cycling stability, which can maintain at 412 mAh g〈sup〉-1〈/sup〉 after 1000 cycles at 5 A g〈sup〉−1〈/sup〉. As anode materials of sodium ion batteries, NS〈sub〉1-1〈/sub〉 can still reach 745.2 mA h g〈sup〉−1〈/sup〉 at 100 mAg〈sup〉-1〈/sup〉 after 100 cycles. At a high current density (5 A g〈sup〉-1〈/sup〉), the reversible capacity is 272.5 mA h g〈sup〉−1〈/sup〉 after 1000 cycles, which exhibits excellent electrochemical performance and cycle stability. The preeminent electrochemical performance can be attributed to three effects: (1) the high level of sulfur and nitrogen; (2) the synergic effect of dual-doping heteroatoms; (3) the large quantity of edge defects and abundant micropores and mesopores, providing extra Li/Na storage regions. This disordered porous biocarbon co-doped with nitrogen/sulfur exhibits unique features, which is very suitable for anode materials of lithium/sodium ion batteries.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323572-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Zhilong Wei, Haisheng Zhen, Jin Fu, Chunwah Leung, Chunshun Cheung, Zuohua Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The laminar burning velocities of biogas-hydrogen-air mixture at different fuel compositions and equivalence ratios were determined and studied using the spherical flame method. The combined effects of H〈sub〉2〈/sub〉 and CO〈sub〉2〈/sub〉 on the laminar burning velocity were investigated quantitatively based on the kinetic effects and the thermal effects. The results show that the laminar burning velocities of the BG40, BG50 and BG60 are increased almost linearly with the H〈sub〉2〈/sub〉 addition owing to the improved fuel kinetics and the increased adiabatic flame temperature. The dropping trend of laminar burning velocity from the BG60-hydrogen to the BG40-hydrogen is primarily attributed to the decreased adiabatic flame temperature (thermal effects). The GRI 3.0 mechanism can predict the laminar burning velocity of biogas-hydrogen mixture better than the San Diego mechanism in this study. Whereas, the GRI mechanism still needs to be modified properly for the hydrogen-enriched biogas as the CO〈sub〉2〈/sub〉 proportion exceeds 50% in the biogas at the fuel-rich condition. The increased CO〈sub〉2〈/sub〉 exerts the stronger suppression on the net reaction rate of H + O〈sub〉2〈/sub〉=OH + O than that of H + CH〈sub〉3〈/sub〉(+M) = CH〈sub〉4〈/sub〉(+M), which contributes to that the rich-shift of peak laminar burning velocity of biogas-hydrogen mixture requires higher H〈sub〉2〈/sub〉 addition as the CO〈sub〉2〈/sub〉 content is enhanced. For the biogas-hydrogen fuel, the H〈sub〉2〈/sub〉 addition decreases the flame stability of biogas fuel effectively due to the increased diffusive-thermal instability and hydrodynamic instability. The improved flame stability of biogas-hydrogen fuel with the increased CO〈sub〉2〈/sub〉 content is resulted from the combined effects of diffusive-thermal instability and hydrodynamic instability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Guorui Zhang, Qi Li, Weirong Chen, Xiang Meng, Huiwen Deng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to improve the robustness of the energy management system (EMS) and avoid the influence of demand power on the design of EMS, a coupled power-voltage equilibrium strategy based on droop control (CPVE-DC) is proposed in this paper. Making use of the principal that the DC bus can directly reflect the changes of load power, the proposed strategy couples DC bus voltage with output powers through droop control to achieve self-equilibrium. The proposed EMS is applied into a hybrid tramway model configured with multiple proton exchange membrane fuel cell (PEMFC) systems, batteries and super capacitors (SCs). FC systems and SC systems are responsible for satisfying most of the demand power, therefore the CPVE-DC strategy generates FCs and SCs reference power through power-voltage droop control on the primary control. Then batteries supplement the rest part of load power and generate DC bus voltage reference value of the next sampling time. With the gambling between output power and DC bus voltage, the hybrid system achieves self-equilibrium and steps into steady operation by selecting appropriate droop coefficients. Then the secondary control of the proposed strategy allocates power between every single unit. In addition, a penalty coefficient is introduced to balance SOC of SCs. The proposed strategy is tested under a real drive cycle LF-LRV on RT-LAB platform. The results demonstrate that the proposed strategy can achieve self-equilibrium and is effective to allocate demand power among these power sources，achieve active control for the range of DC bus voltage and SOC consensus of SCs as well. In addition, some faults are simulated to verify the robustness of the proposed strategy and it turns out that the CPVE-DC strategy possesses higher robustness. Finally, the CPVE-DC strategy is compared with equivalent consumption minimization strategy (ECMS) and the results shows that the proposed strategy is able to get higher average efficiency and lower equivalent fuel consumption.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 26 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 36〈/p〉 〈p〉Author(s): Alexander N. Bondarchuk, Iván Corrales-Mendoza, Sergio A. Tomás, Frank Marken〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Photoelectrochemical water splitting using solar energy is a highly promising technology to produce hydrogen as an environmentally friendly and renewable fuel with high-energy density. This approach requires the development of appropriate photoelectrode materials and substrates, which are low-cost and applicable for the fabrication of large area electrodes. In this work, hematite photoelectrodes are grown by aerosol assisted chemical vapour deposition (AA-CVD) onto highly-conductive and bulk porous SnO〈sub〉2〈/sub〉 (Sb-doped) ceramic substrates. For such photoelectrodes, the photocurrent density of 2.8 mA cm〈sup〉-2〈/sup〉 is achieved in aqueous 0.1 M NaOH under blue LED illumination (〈em〉λ〈/em〉 = 455 nm; 198 mW cm〈sup〉-2〈/sup〉) at 1.23 V vs. RHE (reversible hydrogen electrode). This relatively good photoelectrochemical performance of the photoelectrode is achieved despite the simple fabrication process. Good performance is suggested to be related to the three-dimensional morphology of the porous ceramic substrate resulting in excellent light-driven charge carrier harvesting. The porosity of the ceramic substrate allows growth of the photoactive layer (SnO〈sub〉2〈/sub〉-grains covered by hematite) to a depth of some micrometers, whereas the thickness of Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-coating on individual grains is only about 100–150 nm. This architecture of the photoactive layer assures a good light absorption and it creates favourable conditions for charge separation and transport.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): J. Büsselmann, M. Rastedt, V. Tullius, K. Yezerska, A. Dyck, P. Wagner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the help of consistent conditions for improved batch production and defined quality standards, the lifetime of fuel cell systems should be improved and cost-intensive losses should be minimized at an early state in the production process. Within this work, we concentrated on two accelerated stress tests: load cycling at high current densities and start/stop cycling to compare high temperature (HT) polymer electrolyte membrane (PEM) membrane electrode assemblies (MEAs) of three suppliers to evaluate performances and degradation rates under such conditions. These MEAs have been investigated in-situ via electrochemical characterization. MEAs of three providers differ significantly in their performance and power output for both operation strategies. It was also shown that load cyclization causes greater stress on the MEA than start/stop cycling. Next to the manufacturer comparison, a batch-to-batch evaluation of one provider has been performed including micro-computed tomography (μ-CT) investigations and the determination of the tortuosity of the cathode side gas diffusion layers.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Gisela Orcajo, Helena Montes-Andrés, José A. Villajos, Carmen Martos, Juan A. Botas, Guillermo Calleja〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The organometallic Li-Crown ether species, formed by the complexation of lithium cation with the hydrophobic 18Crown6 ether, has been included in three Metal-Organic-Framework〈del〉s〈/del〉 (MOF) structures with different pore size: Cr-MIL-101, Fe-MIL100 and Ni-MOF-74. X-ray powder diffraction, thermogravimetric analysis, proton nuclear magnetic resonance, infrared spectroscopy and inductively coupled plasma atomic emission spectroscopy measurements have proved the successful incorporation of the organometallic units to the three MOFs without altering their crystalline structure. Hydrogen adsorption properties of the post-synthesis modified materials have been evaluated in a wide temperature (77–298 K) and pressure (1–170 bar) range conditions. The post-synthetic modification method used based on the MOF impregnation with a Li-Crown ether complex solution produced a partial pore blocking effect on the microporous Ni-MOF-74, reducing its hydrogen adsorption capacity. However, the inclusion of the crown-ether and particularly the Li-Crown ether complex resulted in an increase of the volumetric hydrogen adsorption capacity at room temperature for Cr-MIL101 and Fe-MIL-100, due to the pore volume reduction, higher confinement of H〈sub〉2〈/sub〉 molecules in the cavities and the formation of new specific binding sites for H〈sub〉2〈/sub〉 molecules. The inclusion of Li-Crown ether complex also enhances the H〈sub〉2〈/sub〉 interaction with the mesoporous MOF structures, attributed to the additional electrostatic interactions produced by the presence of Li〈sup〉+〈/sup〉 ions complexed to the crown ether molecules. Further work following this strategy to improve hydrogen adsorption capacity of mesoporous MOFs at room temperature should be extended to other MOF materials, checking its influence on their capacity for gas separation purposes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Quentin Bellouard, Sylvain Rodat, Stéphane Abanades, Serge Ravel, Pierre-Éric Frayssines〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of concentrated solar energy as the high-temperature heat source for the thermochemical gasification of biomass is a promising prospect for producing CO〈sub〉2〈/sub〉-neutral chemical fuels (syngas). The solar process saves biomass resource because partial combustion of the feedstock is avoided, it increases the energy conversion efficiency because the calorific value of the feedstock is upgraded by the solar power input, and it also reduces the need for downstream gas cleaning and separation because the gas products are not contaminated by combustion by-products. A new concept of solar spouted bed reactor with continuous biomass injection was designed in order to enhance heat transfer in the reactor, to improve the gasification rates and gas yields by providing constant stirring of the particles, and to enable continuous operation. Thermal simulations of the prototype were performed to calculate temperature distributions and validate the reactor design at 1.5 kW scale. The reliable operation of the solar reactor based on this new design was also experimentally demonstrated under real solar irradiation using a parabolic dish concentrator. Wood particles were continuously gasified at temperatures ranging from 1100 °C to 1300 °C using either CO〈sub〉2〈/sub〉 or steam as oxidizing agent. Carbon conversion rates over 94% and gas productions over 70 mmol/g〈sub〉biomass〈/sub〉 were achieved. The energy contained in the biomass was upgraded thanks to the solar energy input by a factor of up to 1.21.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S036031991831334X-fx1.jpg" width="244" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Antonio Valente, Diego Iribarren, Javier Dufour〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The environmental sustainability of hydrogen energy systems is often evaluated through Life Cycle Assessment (LCA). In particular, environmental suitability is usually determined by comparing the life-cycle indicators calculated for a specific hydrogen energy system with those of a reference system (e.g., conventional hydrogen from steam methane reforming, SMR-H〈sub〉2〈/sub〉). In this respect, harmonisation protocols for comparative LCA of hydrogen energy systems have recently been developed in order to avoid misleading conclusions in terms of carbon footprints and cumulative energy demand. This article expands the scope of these harmonisation initiatives by addressing a new life-cycle indicator: acidification. A robust protocol for harmonising the acidification potential of hydrogen energy systems is developed and applied to both SMR-H〈sub〉2〈/sub〉 and a sample of case studies of renewable hydrogen. According to the results, unlike other energy systems, there is no correlation between acidification and carbon footprint in the case of hydrogen energy systems, which prevents the estimation of harmonised acidification results from available harmonised carbon footprints. Nevertheless, an initial library of harmonised life-cycle indicators of renewable hydrogen is now made available.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Paul Brack, S.E. Dann, K.G.U. Wijayantha, Paul Adcock, Simon Foster〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ferrosilicon 75, a 50:50 mixture of silicon and iron disilicide, has been activated toward hydrogen generation by processing using ball milling, allowing a much lower concentration of sodium hydroxide (2 wt %) to be used to generate hydrogen from the silicon in ferrosilicon with a shorter induction time than has been reported previously. An activation energy of 62 kJ/mol was determined for the reaction of ball-milled ferrosilicon powder with sodium hydroxide solution, which is around 30 kJ/mol lower than that previously reported for unmilled ferrosilicon. A series of composite powders were also prepared by ball milling ferrosilicon with various additives in order to improve the hydrogen generation properties from ferrosilicon 75 and attempt to activate the silicon in the passivating FeSi〈sub〉2〈/sub〉 component. Three different classes of additives were employed: salts, polymers and sugars. The effects of these additives on hydrogen generation from the reaction of ferrosilicon with 2 wt% aqueous sodium hydroxide were investigated. It was found that composites formed of ferrosilicon and sodium chloride, potassium chloride, sodium polyacrylate, sodium polystyrene sulfonate-co-maleic acid or fructose showed reduced induction times for hydrogen generation compared to that observed for ferrosilicon alone, and all but fructose also led to an increase in the maximum hydrogen generation rate. In light of its low cost and toxicity and beneficial effects, sodium chloride is considered to be the most effective of these additives for activating the silicon in ferrosilicon toward hydrogen generation. Materials characterisation showed that neither ball milling on its own nor use of additives was successful in activating the FeSi〈sub〉2〈/sub〉 component of ferrosilicon for hydrogen generation and the improvement in rate and shortening of the induction period was attributed to the silicon component of the mixture alone The gravimetric storage capacity for hydrogen in ferrosilicon 75 is therefore maintained at only 3.5% rather than the 10.5% ideally expected for a material containing 75% silicon. In light of these results, ferrosilicon 75 does not appear a good candidate for hydrogen production in portable applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Ioan Iordache, Karel Bouzek, Martin Paidar, Karin Stehlík, Johannes Töpler, Mirosław Stygar, Juliusz Dąbrowa, Tomasz Brylewski, Ioan Stefanescu, Mihaela Iordache, Dorin Schitea, Sergey A. Grigoriev, Vladimir N. Fateev, Viacheslav Zgonnik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The article contains examples about hydrogen research and development progress in different countries: Czech Republic, Poland, Romania, Russia and Ukraine. Each chapter describes a specific situation for a country and one of them describes some aspects from Germany for comparison with one of international leaders. The examples described into articles are not aleatory. The intention of the authors is to give to the reader the possibility to understand the concrete examples about what means the state of hydrogen and fuel cell research and innovation in the Central and Eastern European countries. The chapters dedicated to Czech Republic, Poland, and Romania, reveal the commitment of these countries in this adventure, often viewed today as a subject of very advanced countries. The specific situation in the Russia Federation describes a strong background, an uncertain present and a questionable future for the hydrogen and fuel cell technology. Development of hydrogen technologies and fuel cells in Ukraine have a long history, also. All of that, in the EU context, by voice of the main stakeholders, considered the hydrogen and fuel cell a decisive issue, with economic and societal ramifications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Evangelos I. Gkanas, Thomas Statheros, Martin Khzouz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A numerical study fully validated with solid experimental results is presented and analysed, regarding the hydrogenation process of rectangular metal hydride tanks for green building applications. Based on a previous study conducted by the authors, where the effective heat management of rectangular tanks by using plain embedded cooling tubes was analysed, in the current work the importance of using extended surfaces to enhance the thermal properties and the hydrogenation kinetics is analysed. The studied extended surfaces (fins) were of rectangular shape; and several combinations regarding the number of fins and the fin thickness were examined and analysed. The values for fin thickness were 2-3-5 and 8 mm and the number of fins studied were 10-14-18 and 20. To evaluate the effect of the heat management process, a modified version of a variable named as Non-Dimensional Conductance (NDC) is introduced and studied. A novel AB〈sub〉2〈/sub〉-Laves phase intermetallic was considered as the metal hydride for the study. The results of the hydrogenation behaviour for the introduced parameters (fin number and thickness) showed that the rectangular tank equipped with the cooling tubes in combination with 14 fins of 5 mm fin thickness has the capability of storing hydrogen over 90% of its theoretical capacity in less than 30 min.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 4 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Zhao-Hui Ruan, Yu-Dong Li, Yuan Yuan, Kai-Feng Lin, He-Ping Tan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As is reported, the photocatalytic activity will increase significantly when TiO〈sub〉2〈/sub〉 nanoparticles are agglomerated into TiO〈sub〉2〈/sub〉 nanofibers (NFs), but the photocatalytic activity enhancement mechanisms are still not fully understood. As is widely accepted, the optical absorption process plays a key role in photocatalysis, and it can even be said that the optical absorption capability of the photocatalyst directly determines its photocatalytic activity, while the influence of the structure on the optical absorption characteristics of TiO〈sub〉2〈/sub〉 has largely been ignored in the existing explanations. In this paper, optical simulations are introduced into analyzing optical characteristics of TiO〈sub〉2〈/sub〉 Nanofibers with which, the photocatalytic activity enhancement mechanism is further discussed, and a photocatalytic activity enhancement mechanism of TiO〈sub〉2〈/sub〉 Nanofibers is proposed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Chenhuan Zhao, Xuegang Liu, Wenqiang Zhang, Yun Zheng, Yifeng Li, Bo Yu, Jianchen Wang, Jing Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To make full use of the advantages of solid oxide cells (SOCs) under actual operating conditions, hetero-structured La〈sub〉0.6〈/sub〉Sr〈sub〉0.4〈/sub〉CoO〈sub〉3-δ〈/sub〉/LaSrCoO〈sub〉4±δ〈/sub〉 (LSC〈sub〉113/214〈/sub〉) thin film electrodes are prepared and investigated by a novel high temperature micro-probe electrochemical test platform for SOCs. The results show that the surface exchange coefficient (k〈sup〉q〈/sup〉) of LSC〈sub〉113/214〈/sub〉 thin films is 3–10 times higher than that of single phase LSC〈sub〉113〈/sub〉 in 773–1123 K. ToF-SIMS and XPS characterizations show that LSC〈sub〉113/214〈/sub〉 hetero-interface leads to Sr enrichment at interfacial region and stabilizes it against detrimental Sr segregation. This hetero-interface further induces increased number of active oxygen vacancies and leads to accelerated oxygen exchange kinetics by raising O 2p center closer to Fermi level. This work provides significantly enhanced ORR/OER activity of hetero-structured LSC〈sub〉113/214〈/sub〉 oxygen electrode at operation conditions and brings substantial technical benefits for the SOC systems.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Penghui Feng, Luying Zhu, Yang Zhang, Fusheng Yang, Zhen Wu, Zaoxiao Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the well-known solid hydrogen storage materials, metal hydrides (MHs) have been developed systematically for decades. During recent years, due to the development of thermal energy storage (TES) market, they have also received much attention gradually as the excellent TES materials because of the high energy density, low cost, and good reversibility. In this study, the stabilized discharging performance of an MH reactor for TES was investigated by numerical simulation. A mathematical model combining multi-physics and proportional-integral controller was established. Based on finite-time thermodynamics, gravimetric exergy-output rate (〈em〉GEOR〈/em〉) considering the control requirement, finite-material, and finite-time constraints was defined. For a given reactor, the output temperature setting could be optimized based on 〈em〉GEOR〈/em〉. Besides, the effects of the reactor parameters on the optimum output temperature setting were systematically studied. The heat transfer analysis indicated the occurrence of the axial non-uniform reaction in the bed due to the inherent increase in the temperature of heat transfer fluid, resulting in the decrease of both 〈em〉GEOR〈/em〉 and material availability. Accordingly, a new tapered bed structure (〈em〉L〈/em〉/〈em〉D〈/em〉〈sub〉o〈/sub〉 = 600/50 mm) was proposed to effectively improve the discharging efficiency from 76 to 90% and 〈em〉GEOR〈/em〉 from 65 to 120 W kg〈sup〉−1〈/sup〉, which provides a helpful guidance for the advanced designing and construction of MH reactor for the practical TES applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 4 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): P. Karthik, T.R. Naveen Kumar, B. Neppolian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Graphitic carbon nitride (g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) is one of the promising two-dimensional metal-free photocatalysts for solar water splitting. Regrettably, the fast electron-hole pair recombination of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 reduces their photocatalytic water splitting efficiency. In this work, we have synthesized the CuO/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 heterojunction via wet impregnation followed by a calcination method for photocatalytic H〈sub〉2〈/sub〉 production. The formation of CuO/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 heterojunction was confirmed by XRD, UV–vis and PL studies. Notably, the formation of heterojunction not only improved the optical absorption towards visible region and also enhanced the carrier generation and separation as confirmed by PL and photocurrent studies. The photocatalytic H〈sub〉2〈/sub〉 production results revealed that CuO/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalyst demonstrated the increased photocatalytic H〈sub〉2〈/sub〉 production rate than bare g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉. The maximum H〈sub〉2〈/sub〉 production rate was obtained with 4 wt % CuO loaded g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalyst. Importantly, the rate of H〈sub〉2〈/sub〉 production was further improved by introducing simple redox couple Co〈sup〉2+〈/sup〉/Co〈sup〉3+〈/sup〉. Addition of Co〈sup〉2+〈/sup〉 during photocatalytic H〈sub〉2〈/sub〉 production shuttled the photogenerated holes by a reversible conversion of Co〈sup〉2+〈/sup〉 to Co〈sup〉3+〈/sup〉 with accomplishing water oxidation. The effective shuttling of photogenerated holes decreased the election-hole pair recombination and thereby enhancing the photocatalytic H〈sub〉2〈/sub〉 production rate. It is worth to mention that the addition of Co〈sup〉2+〈/sup〉 with 4 wt % CuO/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalyst showed ∼7.5 and ∼2.0 folds enhanced photocatalytic H〈sub〉2〈/sub〉 production rate than bare g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Co〈sup〉2+〈/sup〉 and CuO/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalysts. Thus, we strongly believe that the present simple redox couple mediated charge carrier separation without using noble metals may provide a new idea to reduce the recombination rate.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919322566-fx1.jpg" width="268" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): B.A. Braz, V.B. Oliveira, A.M.F.R. Pinto〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉A great challenge in a passive direct methanol fuel cell (pDMFC) is how to reduce both methanol and water crossover, from the anode to the cathode side, without significant losses on its power output. Different approaches including improving the membrane and modifying the cell structure and materials have been proposed in the last years.〈/p〉 〈p〉In this work, an experimental study was carried out to evaluate the effect of the cathode diffusion layer (CDL) properties on the power output of a pDMFC. Towards a cost reduction, lower catalyst loadings were used on both anode and cathode electrodes. Since the main goal was the optimization of a pDMFC using the materials commercially available, different carbon-fibber materials were employed as CDL. The experimental results were analysed based on the polarization curves and electrochemical impedance spectroscopy measurements with innovative electric equivalent circuit allowing the identification of the different losses, including the activation resistance of the parasitic cathode methanol oxidation.〈/p〉 〈p〉A maximum power density of 3.0 mW/cm〈sup〉2〈/sup〉 was obtained using carbon cloth with a lower thickness as CDL and a methanol concentration of 5 M.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): A. Herrmann, A. Mädlow, H. Krause〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The project H2home – decentralised energy supply by hydrogen fuel cells – is part of the HYPOS initiative (Hydrogen Power Storage & Solutions East German) and has the aim to develop an embedded system suitable for the highly efficient use of electrical, thermal and cooling energy provided by green hydrogen in domestic applications. This system is characterized by a hydrogen CHP plant based on a low temperature PEM fuel cell and a hydrogen-based heat generator module with the application of condensation technology as well as an integrated solution for the use of electrical energy in an AC and DC grid through power electronic components. The electric efficiency of the CHP is nearly 50% and the total efficiency higher than 95%.〈/p〉 〈p〉To evaluate the performance of the proposed technology the first step was to model a reference case using the simulation tool TRNSYS〈sup〉®〈/sup〉. Therefore, a multi-family house with 16 residential units was chosen. Within the next step different technologies for the energy supply in complex buildings were identified and evaluated. For this purpose, various Key Performance Indicators (KPI's) have been defined and summarized in three main groups allowing a technical, ecological and economical comparison of the selected technologies. The method as well as the main results of the KPI investigations will be explained in the present paper.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Karin Stehlík, Martin Tkáč, Karel Bouzek〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Although activities in hydrogen technologies in the Czech Republic date back to the 60'ies of the 20th century, significant progress in research and implementation appeared only in the 21st century. The acceleration is linked to the foundation of the Czech Hydrogen Technology Platform (HYTEP) in 2007. The mission of HYTEP is to inform and coordinate implementation of hydrogen economy in the Czech Republic.〈/p〉 〈p〉The last three years brought visible changes. The most important one is that hydrogen mobility is part of the national action plan for clean mobility. During the conference WHTC 2017 in Prague the Ministry of Transport and the Ministry of Environment announced support for construction of over 100 hydrogen refilling stations and more than 100,000 hydrogen cars and buses until 2030. Thanks to this governmental activities also first commercial subject developed plans how utilize the potential of hydrogen technologies.〈/p〉 〈p〉In the future HYTEP has the ambition to initiate coordination with other former East Bloc countries. The objective is to strengthen active participation of this region in European efforts and to link it to European networks and strategies to turn regional stakeholders into active participants in hydrogen technologies.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Wei-Chieh Chung, Yun-En Lee, Moo-Been Chang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Anthropogenic emission of CH〈sub〉4〈/sub〉 and CO〈sub〉2〈/sub〉 contributes for most of global warming. Hence, simultaneous conversion of CH〈sub〉4〈/sub〉 and CO〈sub〉2〈/sub〉 into syngas (dry reforming of methane) can be a promising way to alleviate climate change. In this work, we developed a series of perovskite-type photocatalysts, based on LaFeO〈sub〉3〈/sub〉 with various calcination temperatures to combine with a spark discharge reactor to form a hybrid plasma photocatalysis reactor. The hybrid reactor is applied for dry reforming of methane to investigate the syngas generation rate and to reveal possible interactions between plasma and photocatalyst. Results show that LFO600-packed bed has the best CH〈sub〉4〈/sub〉 and CO〈sub〉2〈/sub〉 conversions and syngas generation efficiency of 53.6%, 40.0% and 18.4 mol/kWh, respectively. The enhancement of syngas generation rate can be attributed to synergies between LFO and plasma. Furthermore, changing calcination temperature of photocatalyst also leads to variable characteristics of photocatalyst and hence plasma photocatalysis performance for syngas production.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Odtsetseg Myagmarjav, Jin Iwatsuki, Nobuyuki Tanaka, Hiroki Noguchi, Yu Kamiji, Ikuo Ioka, Shinji Kubo, Mikihiro Nomura, Tetsuya Yamaki, Shinichi Sawada, Toshinori Tsuru, Masakoto Kanezashi, Xin Yu, Masato Machida, Tatsumi Ishihara, Hiroaki Abekawa, Masahiko Mizuno, Tomoyuki Taguchi, Yasuo Hosono, Yoshiro Kuriki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thermochemical hydrogen production has attracted considerable interest as a clean energy solution to address the challenges of climate change and environmental sustainability. The thermochemical water-splitting iodine-sulfur (IS) process uses heat from nuclear or solar power and thus is a promising next-generation thermochemical hydrogen production method that is independent of fossil fuels and can provide energy security. This paper presents the current state of research and development (R&D) of the IS process based on membrane techniques using solar energy at a medium temperature of 600 °C. Membrane design strategies have the most potential for making the IS process using solar energy highly efficient and economical and are illustrated here in detail. Three aspects of membrane design proposed herein for the IS process have led to a considerable improvement of the total thermal efficiency of the process: membrane reactors, membranes, and reaction catalysts. Experimental studies in the applications of these membrane design techniques to the Bunsen reaction, sulfuric acid decomposition, and hydrogen iodide decomposition are discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Yi-Hsuan Liang, Ming-Wei Liao, Mrinalini Mishra, Tsong-Pyng Perng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on the Z-scheme mechanism, the combination of two semiconductors with suitable bandgaps can reduce the recombination rate of electrons and holes in a single material to enhance photocatalytic hydrogen evolution. Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉 with suitable band gap positions is a potentially promising material for photocatalysis. In order to raise the hydrogen production rate, ZnO nanocrystals were deposited by atomic layer deposition (ALD) on Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉 to form a direct Z-scheme structure, ZnO@Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉. The ALD cycle number varied from 200 to 500. All of the direct Z-scheme samples exhibited much higher hydrogen evolution efficiencies than Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉, ZnO, and the indirect Z-scheme, with the order of ZnO300@Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉〉ZnO200@Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉〉ZnO400@Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉〉ZnO500@Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉. Because of the uniform distribution, discrete particles, and proper size of ZnO, ZnO300@Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉 showed the highest hydrogen evolution rate, being about 500 μmol/g-h. With 400 or 500 ALD cycles, the larger particles of ZnO would overlap with each other to form a continuous layer on Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉, thus reducing the exposure of Ta〈sub〉3〈/sub〉N〈sub〉5〈/sub〉 to the light and water for producing hydrogen.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 4 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Ahmed Sadeq Al-Fatesh, Jehad K. Abu-Dahrieh, Hanan Atia, Udo Armbruster, Ahmed A. Ibrahim, Wasim U. Khan, Ahmed Elhag Abasaeed, Anis H. Fakeeha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the effect of pre-treatment and calcination temperature on a series of 5%Co/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-ZrO〈sub〉2〈/sub〉, 5%Ni/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-ZrO〈sub〉2〈/sub〉 and 2.5%Co-2.5%Ni/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-ZrO〈sub〉2〈/sub〉 catalysts for dry reforming of methane was investigated. Main focus of our research was to improve the catalyst stability by proper pre-treatment and reaction conditions. The first approach aimed at the catalyst pre-treatment by using bimetallic systems and the second strategy at the 〈em〉in situ〈/em〉 suppression of coke. The catalytic activity of bimetallic system was indeed higher compared to the monometallic in the temperature range of 500–800 °C (space velocity 18000 ml h〈sup〉−1〈/sup〉·g〈sub〉cat〈/sub〉〈sup〉−1〈/sup〉, CH〈sub〉4〈/sub〉/CO〈sub〉2〈/sub〉 = 1). The bimetallic catalyst calcined at 800 °C showed highest CH〈sub〉4〈/sub〉 conversion without deactivation and gave a H〈sub〉2〈/sub〉/CO ratio of 91% and 0.96, respectively, and good stability with less coke deposition over 28 h at 800 °C reaction temperature. This improvement is assigned to the synergism between Co and Ni, their high dispersion according to interaction with support. It has been shown in our work that pretreatment temperatures and atmospheres have strong impact on stability of the catalyst. TEM, XRD and TPO investigations confirmed that the slight catalyst deactivation was related to the formation of multiwall carbon nanotubes with hollow inner tube structure. The addition of small amounts of steam or oxygen during DRM improved both the catalyst activity and stability as the bimetallic catalyst lost around 9.4% conversion in DRM, 5.4% in presence of water and only 3.2% in presence of O〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Jakub Kupecki, Ryszard Kluczowski, Davide Papurello, Andrea Lanzini, Michał Kawalec, Mariusz Krauz, Massimo Santarelli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The current study was oriented at analyzing the performance of an anode-supported solid oxide fuel cell produced using high-pressure injection molding. The cell with a total thickness of 550 μm was produced in the Ceramic Department (CEREL) of the Institute of Power Engineering in Poland and experimentally analyzed in the Energy Department (DENERG) of Politecnico di Torino in Italy. The high-pressure injection molding technique was applied to produce a 500 μm thick anode support NiO/8YSZ 66/34 wt% with porosity of 25 vol%. The screen printing method was used to print a 3 μm thick NiO anode contact layer, 7 μm thick NiO/8YSZ 50/50 wt% anode functional layer, 4 μm thick 8YSZ dense electrolyte, 1.5 μm thick Gd〈sub〉0,1〈/sub〉Ce〈sub〉0,9〈/sub〉O〈sub〉2〈/sub〉 barrier layer and a 30 μm thick La〈sub〉0,6〈/sub〉Sr〈sub〉0,4〈/sub〉Fe〈sub〉0,8〈/sub〉Co〈sub〉0,2〈/sub〉O〈sub〉3–δ〈/sub〉 cathode with porosity 25 vol%.〈/p〉 〈p〉The experimental characterization was done at two temperature levels: 750 and 800 °C under fixed anodic and cathodic flow and compositions. The preliminary studies on the application of high-pressure injection molding are discussed together with the advantages of the technology. The performance of two generations of anode-supported cells is compared with data of reference cells with supports obtained using tape casting.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Tian-Feng Hou, Arunkumar Shanmugasundaram, Mostafa Afifi Hassan, Muhammad Ali Johar, Sang-Wan Ryu, Dong-Weon Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In present work, we report a facile fabrication process to improve the photoelectrochemical (PEC) performance of ZnO-based photoelectrodes. In order to achieve that, the Cu〈sub〉2〈/sub〉O nanocubes are cathodic-deposited on the as-prepared ZnO nanorods. Then rGO nanosheets are electrodeposited on the ZnO/Cu〈sub〉2〈/sub〉O heterostructures. The fabricated photoelectrodes are systematically studied in detail by different characterization techniques such as powder X-ray diffraction, micro-Raman, X-ray photoelectron spectroscopy, ultraviolet diffused reflectance spectroscopy and photoluminescence spectroscopy analysis. Morphologies of the fabricated photoelectrodes are investigated through electron microscopy in scanning and transmission mode. To evaluate the PEC performance of the fabricated photoelectrodes, the line scan voltammetry (LSV) measurement is performed using a three-electrode system in 0.5-M Na〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 electrolyte solution under stimulated light illumination at 100 mW/cm〈sup〉2〈/sup〉 from a 300-W Xenon Arc lamp coupled with an AM 1.5G filter using a three-electrode system. The photocurrent measurement demonstrates that the photoelectrodes based on ZnO/Cu〈sub〉2〈/sub〉O/rGO possess enhanced PEC performance compared to the pristine ZnO and ZnO/Cu〈sub〉2〈/sub〉O photoelectrodes. The photocurrent density of ZnO/Cu〈sub〉2〈/sub〉O/rGO-15 photoelectrode (10.11 mA/cm〈sup〉2〈/sup〉) is ∼9 and ∼3 times higher than the photoelectrodes based on pristine ZnO (1.06 mA/cm〈sup〉2〈/sup〉) and ZnO/Cu〈sub〉2〈/sub〉O (3.22 mA/cm〈sup〉2〈/sup〉). The enhanced PEC performance of ZnO/Cu〈sub〉2〈/sub〉O/rGO photoelectrode is attributed to the excellent light absorption properties of Cu〈sub〉2〈/sub〉O and excellent catalytic and charge transport properties of rGO. Experimental results reveal that the proposed functional nanomaterials have a great potential in water splitting applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The improved PEC performance of the ZnO/Cu〈sub〉2〈/sub〉O/rGO hybrid photoelectrodes is attributed to (i) excellent crystalline nature of the as-prepared ZnO NRs and Cu〈sub〉2〈/sub〉O nanocubes, (ii) large light absorption property of the Cu〈sub〉2〈/sub〉O nanocubes, (iii) high electrical conduction effect and excellent charge transport property of the rGO nanosheets, (iv) electric effect induced by the heterojunction between the vertically aligned ZnO NRs, Cu〈sub〉2〈/sub〉O nanocubes and rGO nanosheets (Scheme 2) and (v) excellent electron acceptor and passivation layer of rGO. All these factors coupled together contribute to the excellent PEC performance of ZnO/Cu〈sub〉2〈/sub〉O/rGO hybrid based photoelectrodes.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S036031991831646X-fx1.jpg" width="221" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Masoud Rokni〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fossil fuels are stored energy during millions of years and we are using it in a rate that new fuels cannot be formed. Renewable energies are not available all the time and there is a need to find ways to store them. One way of storing renewable energies is in fuel form, similar to the fossil fuels and then use this stored fuel whenever needed. The plant design proposed in this paper consists of Dish-Stirling collectors supported by a reversible solid oxide cell acting as a power generator and storage unit, and therefore offering dispatchable power on demand. Further, the system reuses the waste heat for seawater desalination. The present work is an analytical study in which the performance evaluation of a self-sustainable polygeneration system with integrated hydrogen production, power generation, and freshwater production is conducted. An evaluation for selected days, representative for summer, fall, winter and spring in an area with low solar irradiation is studies to investigate the potential of this system to supply 500 kW continuously and simultaneously producing a considerable amount of freshwater. The study shows that the plant can produced hydrogen even in low irradiation winter days together with at least 6500 L of freshwater daily.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 26 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 36〈/p〉 〈p〉Author(s): Zhentao Wang, Yanwei Zeng, Chuanming Li, Zhupeng Ye, Yuan Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrochemical properties of bi-layered electrolytes GDC(Gd〈sub〉0.1〈/sub〉Ce〈sub〉0.9〈/sub〉O〈sub〉1.95〈/sub〉)/YSZ(Y〈sub〉0.16〈/sub〉Zr〈sub〉0.84〈/sub〉O〈sub〉1.92〈/sub〉), ESB(Er〈sub〉0.4〈/sub〉Bi〈sub〉1.6〈/sub〉O〈sub〉3〈/sub〉)/GDC and ESB/YSZ with different layer thickness fractions in the temperature range from 400 to 800 °C have been investigated by simulating calculations based on a charge transport continuity equation and the characteristic conductivity parameters of YSZ, GDC and ESB. It has been found that the model cells with ESB/GDC and ESB/YSZ bi-layered electrolytes can render a higher maximum power density that increases with the ESB layer thickness than those with GDC/YSZ bi-layered electrolytes in the studied temperature range. While the oxygen partial pressure at the interface of ESB/GDC is much lower than that of ESB/YSZ electrolyte with the same ESB thickness fraction, a higher interfacial oxygen partial pressure than the critical decomposition value of Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 can be achieved in the ESB/YSZ electrolytes even with small YSZ thickness fractions. This result strongly suggests that the ESB/YSZ, instead of ESB/GDC, would be a thermodynamic stable bi-layered electrolyte with high output power density for potential applications in the intermediate to low temperature SOFCs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Oliver Posdziech, Konstantin Schwarze, Jörg Brabandt〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper describes the development status of Sunfire's reversible solid oxide cell (RSOC) technology. Here, Sunfire is a pioneer in the field of high-temperature electrolysers (HTE) for renewable hydrogen production which can be operated as a fuel cell for power generation in a reverse mode. The maturity of the technology is improved stepwise so that first applications in the field of hydrogen production for industry and electricity storage can be tackled. Three application examples where larger scale prototype has been installed will be discussed: 1) A power-to-power electricity storage based on hydrogen, 2) a RSOC unit that is installed in an iron and steel works, and 3) a pressurized SOEC prototype which will be integrated with a methanation unit. Results show the potentials of the technology in connection with fluctuating renewable energy sources.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Fengzhan Si, Xiaomin Kang, Victoria F. Mattick, Guodong Fu, Xian-Zhu Fu, Kevin Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to design and synthesize oxygen reduction reaction catalysts with high activity and low cost, a series of Co–Mn-oxide/C catalysts with different Co:Mn ratios have been prepared using a hydrothermal method applied in sequential steps. The monotonically systematic trends of the catalysts’ phases, morphologies and particle sizes have been verified, and the trending of Mn ions and Co ions in different valence states follows the increasing Co:Mn ratio. Electrochemical performance of the catalysts in oxygen reduction reaction results in a volcano-type trend with an optimal Co:Mn ratio of 3 giving the best performance, which is comparable to that of commercial Pt/C. Lastly, a Koutecky-Levich approach has been employed to deduce the electron transfer values, in an attempt to rationalize their selectivity towards the varying 2 and 4 electron pathways. The systematic research is significant for understanding and designing a new generation of non-noble metal oxygen reduction reaction catalysts.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 35〈/p〉 〈p〉Author(s): Arul Murugan, Marc de Huu, Thomas Bacquart, Janneke van Wijk, Karine Arrhenius, Indra te Ronde, David Hemfrey〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Uptake of hydrogen vehicles is an ideal solution for countries that face challenging targets for carbon dioxide reduction. The advantage of hydrogen fuel cell electric vehicles is that they behave in a very similar way to petrol engines yet they do not emit any carbon containing products during operation. The hydrogen industry currently faces the dilemma that they must meet certain measurement requirements (set by European legislation) but cannot do so due to a lack of available methods and standards. This paper outlines the four biggest measurement challenges that are faced by the hydrogen industry including flow metering, quality assurance, quality control and sampling.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Pragati Singh, Pardeep K. Jha, Priyanka A. Jha, Prabhakar Singh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sodium bismuth titanate samples with different morphology were synthesized via varying the sintering temperature from 1000 to 1150 °C. The conductivity was significantly affected with the morphology of the system. The dynamics of ions was understood from the conductivity spectra. The dc conductivity, hopping frequency and exponent values were extracted from the conductivity spectra analysis. The impedance and modulus spectroscopy along with exponent behaviour suggested short range hopping for the sample sintered at 1000 °C and followed Ghosh scaling instead of Summerfield scaling. While long-range hopping was observed for the samples sintered at 1150 °C and it followed both the Summerfield scaling and Ghosh scaling. Moreover, the stability of the sample is checked in reducing atmosphere.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323468-fx1.jpg" width="280" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Ruirun Chen, Xin Ding, Xiaoyu Chen, Xinzhong Li, Yanqing Su, Jingjie Guo, Hongsheng Ding, Hengzhi Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nanosizing is efficient as the dual-tuning of thermodynamics and kinetics for Mg-based hydrogen storage materials. The in-situ synthesis of nanocomposites through hydrogen-induced decomposition from long-period stacking ordered phase is proved effective to achieve active nano-sized catalysts with uniform dispersion. In this study, the Mg〈sub〉93〈/sub〉Cu〈sub〉7-〈em〉x〈/em〉〈/sub〉Y〈sub〉〈em〉x〈/em〉〈/sub〉 (〈em〉x〈/em〉 = 0.67, 1.33, and 2) alloys with equalized Mg–Mg〈sub〉2〈/sub〉Cu eutectic and 14H long-period stacking ordered phase of Mg〈sub〉92〈/sub〉Cu〈sub〉3.5〈/sub〉Y〈sub〉4.5〈/sub〉 are prepared. Its solidification path is determined as α-Mg, 14H–Mg〈sub〉2〈/sub〉Cu pair and Mg–Mg〈sub〉2〈/sub〉Cu eutectic. The increased Y/Cu atomic ratio lowers the first-cycle hydrogenation rate of the alloys due to the increased 14H–Mg〈sub〉2〈/sub〉Cu structure and reduced Mg–Mg〈sub〉2〈/sub〉Cu eutectic interfaces. After the hydrogen-induced decomposition of the long-period stacking ordered phase, MgCu〈sub〉2〈/sub〉 and YH〈sub〉3〈/sub〉 nanoparticles are in-situ formed, and the following activation process significantly accelerates. The YH〈sub〉3〈/sub〉 nanoparticles partly decompose to YH〈sub〉2〈/sub〉 at 300 °C in vacuum and Mg–Mg〈sub〉2〈/sub〉Cu-YH〈sub〉〈em〉x〈/em〉〈/sub〉 nanocomposites are in-situ formed. The nano-sized YH〈sub〉2〈/sub〉 helps catalyze H〈sub〉2〈/sub〉 dissociation and the YH〈sub〉〈em〉x〈/em〉〈/sub〉/Mg interfaces stimulate H diffusion and the nucleation of MgH〈sub〉2〈/sub〉. Therefore, the Mg〈sub〉93〈/sub〉Cu〈sub〉5〈/sub〉Y〈sub〉2〈/sub〉 composite shows the fastest absorption rates. However, due to the positive effect of YH〈sub〉〈em〉x〈/em〉〈/sub〉/Mg interfaces on H diffusion and the negative effect of YH〈sub〉3〈/sub〉 nanophases on the hydride decomposition, the minimum activation energy of 115.43 kJ mol〈sup〉−1〈/sup〉 is obtained for the desorption of the Mg〈sub〉93〈/sub〉Cu〈sub〉5.67〈/sub〉Y〈sub〉1.33〈/sub〉 hydride.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323390-fx1.jpg" width="343" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Zhihao Dong, Tong Zhou, Jie Liu, Xinwen Zhang, Bin Shen, Wenbin Hu, Lei Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Stainless steels as proton exchange membrane fuel cell bipolar plates have received extensive attention in recent years. The pack chromizing layer was fabricated on 316L stainless steel to improve the corrosion resistance and electrical conductivity. The corrosion properties were investigated in 0.5 M H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 + 2 ppm HF solution at 70 °C purged with hydrogen gas and air. Higher electrochemical impedance and more stable passive film were obtained by chromizing the 316L stainless steel. Potentiodynamic polarization results showed the corrosion current densities were reduced to 0.264  μA cm〈sup〉−2〈/sup〉 and 0.222  μA cm〈sup〉−2〈/sup〉 in two simulated operating environments. In addition, the interfacial contact resistance was decreased to 1.4 mΩ⋅cm〈sup〉2〈/sup〉 under the compaction force of 140 N⋅cm〈sup〉−2〈/sup〉 and maintained at low values after potentiostatic polarization for 4 h. The excellent corrosion and conductive performances could be attributed to the chromium carbides and high alloying element content in chromizing layer.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323493-fx1.jpg" width="278" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Anshul Gupta, Suboohi Shervani, Flamina Amaladasse, Sri Sivakumar, Kantesh Balani, Anandh Subramaniam〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nickel is a good catalyst for the dissociation of molecular hydrogen to atomic form, but suffers from a negligible hydrogen storage capacity (∼10〈sup〉−4〈/sup〉 wt% at 25 °C and 1 atm). The current investigation pertains to the enhancement in the reversible hydrogen storage capacity of Ni via storage in molecular form; thus utilizing a recently developed multi-mode storage philosophy. Ni nano hollow spheres (NiHS) have been synthesized using hydrothermal method (outer diameter of ∼300 nm and shell thickness ∼30 nm). Pressure-composition-isotherms and temperature programmed desorption curves have been used to characterize the hydrogen storage capacity and to establish the reversibility of the process. An enhancement in the reversible storage capacity by a factor of 7 × 10〈sup〉3〈/sup〉 (7,00,000%) is obtained at 25 °C and 150 bar pressure. The capacity is further enhanced to 0.91 wt% hydrogen by utilizing a pressure of 300 bar. Ni plays a dual catalytic role in the absorption and desorption process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Xiaoqiang Du, Hui Su, Xiaoshuang Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The efficiency and stability of electrocatalysts are the key factors for measuring oxygen evolution reaction. In this work, the MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 structure assembled from well-arranged nanowires or nanosheet arrays has been grown vertically on nickel foam by in-situ hydrothermal method. Interestingly, different morphology of MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 can be easily regulated by adding NH〈sub〉4〈/sub〉F to a mixed solvent to achieve conversion from nanowires to nanosheets. In addition, further synthesis of unique three-dimensional hierarchical core/shell MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS nanowires or nanosheets arrays was performed primarily by electrochemical deposition. Both MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanowires and MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanosheets exhibit high efficiency and long-lasting stability for the oxygen oxidation reaction. The lower overpotential of only 280 mV and 270 mV at 20 mA cm〈sup〉−2〈/sup〉 for the MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanowires and MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanosheets were obtained with lower Tafel slopes of 139. 19 mV dec〈sup〉−1〈/sup〉 and 131.81 mV dec〈sup〉−1〈/sup〉 in 1.0 M potassium hydroxide respectively comparing with our other MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS catalysts. The results demonstrate that the crystal morphology of MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS does not significantly influence their electrocatalytic activity in water oxidation reactions by comparing nanostructured MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS nanowires and MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS nanosheets. The high catalytic activity of the MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS nanoarrays is attributed to the possession of more active sites, larger specific surface area, abundant oxygen vacancy, and fast electron transport rate. Not only that, the durability of the MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS nanoarrays is also excellent after continuous oxygen evolution test of 1000 cycles. The results of XRD, SEM and XPS show that MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanowires and MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanosheets materials can be used as a highly efficient and stable catalyst for oxygen evolution reaction.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The results of XRD, SEM and XPS show that MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanowires and MnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉@CoS-7 cycles nanosheets materials can be used as a highly efficient and stable catalyst for oxygen evolution reaction.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323365-fx1.jpg" width="308" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 12 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 34〈/p〉 〈p〉Author(s): Arzu Kanca, Deniz Uner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Economical valorization of low quality, high sulfur feedstocks is an important challenge. Most of the valorization processes start from pyrolysis, with a significant amount of evolution of sulfur containing compounds. This study addresses in situ and downstream sulfur capture ability of lead oxide (PbO) in comparison to zinc oxide (ZnO) during the pyrolysis of high–sulfur Tuncbilek lignite. In order to assess the role of hydrogen in sulfur capture, hydrogenation experiments were also performed. Sulfidation reaction thermodynamics of PbO and ZnO was compared to most commonly used metal oxides for sulfur capture i.e., FeO, MnO, and CaO. The equilibrium conversions indicated superior performance of PbO and ZnO towards sulfidation reactions at high temperatures. Thermodynamic superiority of PbO sulfidation encouraged us to investigate the PbO as a new sulfur sorbent for hot gas desulfurization. The experimental verification of the high temperature sulfidation ability of PbO and ZnO was performed using high–sulfur Tuncbilek lignite under semibatch conditions. The final compounds formed after each process were observed by X-ray diffractometer (XRD) and Diffuse Reflectance Infrared Fourier Transformation Spectroscopy (DRIFTS). Experiments revealed that PbO can be promising candidate as hot gas sulfur trap during pyrolysis and hydrogenation processes, while ZnO can hold up sulfur only in the presence of hydrogen. Furthermore, both PbO and ZnO show the superior sulfur capture performance in the presence of hydrogen when they were used as adsorbents located after the reactor (downstream) at ambient conditions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 12 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 34〈/p〉 〈p〉Author(s): Mustafa Kaan Baltacioglu, Raif Kenanoglu, Kadir Aydın〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One of the primary aims of this experimental investigation is to examine hydroxy-gas enrichment effects on environmentally friendly but performance-reducing alternative fuels such as ethanol and biodiesel. Hydroxy gas is a product of the pure water electrolysis method. Entire HHO system has integrated into engine test rig for this purpose. Two different biodiesohol fuel blend prepared and named by their volumetric compositions. Biodiesohol used to describe biodiesel, ethanol and standard diesel blends. Specific fuel properties are measured and ensured to be in EN590 and EN14214 standards. Experiments were conducted on a single cylinder diesel engine which was fuelled with diesel-biodiesel-ethanol fuel blends those enriched by 1 L per minute HHO gas during the entire tests. All of the experiments performed under full load condition within the range of 1200–3200 rpm engine speed. From the view of performance; brake power, brake specific fuel consumption and thermal efficiency results discussed. Besides, carbon monoxide and nitrogen oxides results measured and presented as exhaust emission. Standard diesel fuel outputs determined as a reference line to analyze the changes. A number of studies have been conducted with fuels used in this experimental study and their mixture in different ratios as well, but an examination of the HHO addition to biodiesel is performed for the first time in this research area of the literature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 12 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 34〈/p〉 〈p〉Author(s): Yusuf Bicer, Ibrahim Dincer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The study presented here concerns a comprehensive investigation on exergoeconomic analysis and optimization of an integrated system for photoelectrochemical hydrogen and electrochemical ammonia production. The present integrated system consists of a solar concentrator, spectrum-splitting mirrors, a photoelectrochemical hydrogen production reactor, a photovoltaic module, an electrochemical ammonia production reactor and support mechanisms. Detailed thermodynamic and exergoeconomic analyses are initially conducted to determine the performance of the integrated system namely; efficiency and total cost rate. The obtained performance parameters are then optimized to yield the minimum cost rate and maximum efficiency under given constraints of the experimental system. The highest capital cost rates are observed in the photoelectrochemical hydrogen and electrochemical ammonia production reactors because of high procurement costs and electricity inputs. The optimized values for exergy efficiency of the integrated system range from 5% to 9.6%. The photovoltaic and photoelectrochemical cell areas and solar light illumination mainly affect the overall system efficiencies. The optimum efficiencies are found to be 8.7% and 5% for the multi-objective optimization of hydrogen production and integrated ammonia production system, respectively. When the exergy efficiency of the integrated system is maximized and the total cost rate is minimized at the same time, the total cost rate of the system is calculated to be about 0.2 $/h. The cost sensitivity analysis results of the present study show that the total cost rate of the system is mostly affected by the interest rate and lifetime of the system.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319918332518-fx1.jpg" width="266" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 12 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 34〈/p〉 〈p〉Author(s): Gobeng R. Monama, Kwena D. Modibane, Kabelo E. Ramohlola, Kerileng M. Molapo, Mpitloane J. Hato, Mogwasha D. Makhafola, Gloria Mashao, Siyabonga B. Mdluli, Emmanuel I. Iwuoha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Copper(II)phthalocyanine-incorporated metal organic framework (CuPc/MOF) composite material was synthesized for application as an electrocatalyst for hydrogen evolution reaction (HER). The composite exhibited excellent electroactivity compared to the unmodified MOF, as confirmed by the diffusion coefficients (〈em〉D〈/em〉) values of 3.89 × 10〈sup〉−7〈/sup〉 and 1.57 × 10〈sup〉−6〈/sup〉 cm〈sup〉2〈/sup〉 s〈sup〉−1〈/sup〉 for MOF and CuPc/MOF, respectively. The 〈em〉D〈/em〉 values were determined from cyclic voltammetry (CV) experiments performed in 0.1 mol L〈sup〉−1〈/sup〉 tetrabutylammonium perchlorate/dimethyl sulfoxide (TBAP/DMSO) electrolyte. The Tafel slope determined from the CV data of CuPc/MOF-catalysed HER for 0.450 mol L〈sup〉−1〈/sup〉 H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉, was 176.2 mV dec〈sup〉−1〈/sup〉, which was higher than that of the unmodified MOF (158.3 mV dec〈sup〉−1〈/sup〉). The charge transfer coefficients of MOF and CuPc/MOF were close to 0.5, signifying the occurrence of a Volmer reaction involving either the Heyrovsky or the Tafel mechanism for hydrogen generation. For both MOF and CuPc/MOF, the exchange current density (〈em〉i〈/em〉〈sub〉0〈/sub〉) improved with increase in the concentration of the hydrogen source (i.e. 0.033–0.45 mol L〈sup〉−1〈/sup〉 H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉) Nonetheless, the CuPc/MOF composite had a higher 〈em〉i〈/em〉〈sub〉0〈/sub〉 value compared with the unmodified MOF. Thus CuPc/MOF has promise as an efficient electrocatalyst for HER.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 12 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 34〈/p〉 〈p〉Author(s): Ramazan Solmaz, Hilmi Yurdakul〈/p〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Prashant Sharma, Sandeep Gupta, Rini Singh, Kanad Ray, S.L. Kothari, Soumendu Sinha, Rishi Sharma, Ravindra Mukhiya, Kamlendra Awasthi, Manoj Kumar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present paper, Na〈sub〉3〈/sub〉BiO〈sub〉4〈/sub〉–Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 films have been tested for hydrogen ion sensing. Na〈sub〉3〈/sub〉BiO〈sub〉4〈/sub〉–Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 mixed oxide nanostructures were deposited on the Indium–Tin-Oxide (ITO) coated glass substrate using a low-cost electrodeposition technique at room temperature. The nanostructures have been characterized using FESEM and XPS to study their morphology and composition, respectively. Vertically aligned nanostructures (thickness~90 nm) with well-defined edges were seen in FESEM studies. XPS analysis indicates the presence of Na〈sub〉3〈/sub〉BiO〈sub〉4〈/sub〉 and Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉. The crystallinity and the mixed phase of the film were further confirmed by X-ray diffraction study. These nanostructures were explored as a potential candidate for pH sensing using them as a sensing film for Extended-Gate Field-Effect Transistor (EGFET). A sensitivity of 49.63 mV/pH has been observed with good linearity. To the best of our knowledge, for the first time vertically aligned Na〈sub〉3〈/sub〉BiO〈sub〉4〈/sub〉–Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 mixed oxide nanostructures are demonstrated as an EGFET-based (Hydrogen ion) pH sensor.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Yang Zhang, Tian Zhang, Zhiping Zhang, Nadeem Tahir, Quanguo Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a perennial grass, 〈em〉Humulus scandens〈/em〉 is rich in cellulose which can be fermented for bioenergy producing. Hence, the hydrogen production potential of the 〈em〉Humulus scandens〈/em〉 from dark fermentation by 〈em〉Enterobacter aerogenes〈/em〉 was investigated in this paper. Cellulase amount, inoculation amount, and initial pH value were evaluated. The interrelationship between these factors were studied by Response Surface Box-Behnken Experiments. Results showed that there was a significant correlation between the three factors. Through the correction of the regression equation, the optimized technological conditions were obtained. The amount of cellulase was 0.203 g g〈sup〉−1〈/sup〉 TS, the inoculation amount was 42.6%, the initial pH value was 6.59, the pre-estimated maximum cumulative value of hydrogen production was 65.12 mL g〈sup〉−1〈/sup〉 TS, and it was similar to the test mean value which was 64.08 mL g〈sup〉−1〈/sup〉 TS.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Harun Yilmaz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Major challenges for micro combustors are high heat losses and inappropriate residence time. In this study, it was aimed to eliminate these challenges via placing bluff bodies into the combustion zone and combusting fuel with oxygen enriched air. To this end, micro combustor models with different geometries were constructed and in these models, premixed H〈sub〉2〈/sub〉/air combustion was simulated by using ANSYS/Fluent CFD code to investigate effects of bluff body shape, location and thickness, and low level O〈sub〉2〈/sub〉 enhancement on performance determining parameters such as rate of conversion of fuel to useable heat, temperature uniformity, pollutant emissions etc. To further analyze effects of micro combustor geometry, a perforated plate was also placed into the combustion zone. Thermal performance of the micro combustor with perforated plate insertion in O〈sub〉2〈/sub〉 enriched conditions was found to be highest in terms of increased reaction kinetics and heat transfer characteristics. The trade-offs of respective design are increased NO〈sub〉x〈/sub〉 emissions and slightly decreased temperature uniformity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Sujoy Bepari, Debasish Kuila〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Depletion of non-renewable energy sources such as coal and natural gas is paving the way to generate alternative energy sources. Hydrogen, a very promising alternative energy has the highest energy density (143 MJ/kg) compared to any known fuel and it has zero air pollution due to the formation of water as the only by-product after combustion. Currently, 95% of hydrogen is produced from non-renewable sources. Hydrogen production from renewable sources is considered a promising route for development of sustainable energy production. Steam reforming of renewable sources such as methanol, ethanol and glycerol is a promising route to hydrogen production. This review covers steam reforming of these three alcohols using Ni-based catalysts with different supports. Chemistry of the steam reforming reactions is discussed. Hydrogen yield depends on operating conditions, the nature of active metal and the catalyst support. Supports play an important role in terms of hydrogen selectivity and catalyst stability because of their basic characteristics and redox properties. Synthesis of suitable catalysts that can suppress coke formation during reforming is suggested.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Sandeep Kumar Lakhera, V.S. Vijayarajan, B.S. Rishi Krishna, Pandiyarasan Veluswamy, Bernaurdshaw Neppolian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To overcome the low photocatalytic efficiency of bulk g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉, herein, we have designed a novel cobalt phosphate hydroxide loaded graphitic carbon nitride photocatalysts by co-precipitation route. The FESEM and HRTEM analysis revealed that in the presence of the phosphorus compound, the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 sheets tend to fold and form a rod-like morphology. The loading of cobalt phosphate hydroxide in g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 resulted in the redshift of the absorption edge. XRD, FTIR and XPS analysis revealed that cobalt phosphate hydroxide is bonded to g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 via electrostatic interaction. The cobalt phosphate hydroxide/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalysts was used for photocatalytic hydrogen evolution and produced nearly 1016 μmol/g of hydrogen in 4 h of reaction time under direct solar light irradiation. This significantly higher activity was accredited to the effective charge carrier separation by cobalt phosphate hydroxide in the photocatalysts, as shown by the photoluminescence and time-resolved photoluminescence (TRPL) measurements. TRPL measurements have shown that Co〈sub〉2〈/sub〉PO〈sub〉4〈/sub〉OH incorporation in g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 leads to a 42% higher lifetime of photogenerated charge carriers. In addition, the Co〈sub〉2〈/sub〉PO〈sub〉4〈/sub〉OH loaded g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalysts retains its photostability even after four cycles of reaction without any significant drop in hydrogen production activity. This work provides a facile approach to synthesize highly stable and efficient visible light active cobalt phosphate hydroxide loaded graphitic carbon nitride photocatalysts for solar energy conversion applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919328381-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 10 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Xinming Du, Hongyu Zhang, Minghui Li, Zhe Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The alternating copolymer based on poly (ether ether ketone) (PEEK) is synthesized with ordered side chain. A series of novel anion exchange membranes grafte with the 1, 2-dimethylimidazole and 1-vinylimidazole are obtained. The copolymer was verified by 〈sup〉1〈/sup〉H NMR and the crosslinked membranes are further investigated by solvability test. The ordered hydrophilic side chains form well-defined microphase separation structure, which are proved by Transmission electron micrographs microscopy (TEM). The ionic conductivity is 0.075 S/cm at 80 °C of Im-PEEK-0 uncross-linked membrane. With the addition of 1-vinylimidazole, the maximum stress increases to 66.57 MPa, the water uptake drop to 17.1% and swelling ratio drop to 14.8% at 80 °C of Im-PEEK-0.3 membrane. The hydroxide conductivity remains 82.8% in 2 mol L〈sup〉−1〈/sup〉 NaOH solution at 60 °C for 400 h. Meanwhile, all the membranes exhibit excellent thermal stability. Overall, the ordered imidazolium-functionalized side chains provide a method to balance hydroxide conductivity and alkali stability of anion exchange membranes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 9 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Vikrant Yadav, Abhishek Rajput, Nehal H. Rathod, Vaibhav Kulshrestha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fuel cells are the promising new non-conventional power source for vehicles as well as portable devices. Direct methanol fuel cell (DMFC) is especially attractive since it uses low cost liquid methanol as a fuel. Proton exchange membrane is one of the most crucial part of DMFC. Herein, we synthesized the sulfonated boron nitride (SBN) based SPEEK composite membranes for the DMFC application. SBN was synthesized by covalent functionalization of hydroxylated BN by using 3-mercaptopropyl trimethoxysilane and sulfonated by subsequent oxidation of mercapto group. Sulfonated poly (ether ether ketone) is used as a polymer matrix for SBN. With well controlled content of SBN into SPEEK matrix exhibit high proton conductivity, IEC and water content along with excellent mechanical strength. Composite membranes show low methanol cross over and high selectivity, which makes them attractive candidate for proton exchange membrane for direct methanol fuel cells.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 10 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Lucas Faccioni Chanchetti, Daniel Rodrigo Leiva, Leandro Innocentini Lopes de Faria, Tomaz Toshimi Ishikawa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen is a promising sustainable energy carrier for the future due to its high energetic content and no emissions, other than water vapor. However, its full deployment still requires technological advances in the renewable and cost-effective production of hydrogen, cost reduction of fuel cells and especially in the storage of hydrogen in a lightweight, compact and safe manner. One way to achieve this is by using materials in which hydrogen bonds chemically, or by adsorption. Different kinds of Hydrogen Storage Materials have been investigated, such as Metal-Organic Frameworks (MOFs), Simple Hydrides (including Magnesium Hydride, MgH〈sub〉2〈/sub〉), AB〈sub〉5〈/sub〉 Alloys, AB〈sub〉2〈/sub〉 Alloys, Carbon Nanotubes, Graphene, Borohydrides, Alanates and Ammonia Borane. Billions have been invested in Storage Materials research, resulting in tens of thousands of papers. Thus, it is challenging to track how much effort has been devoted to each materials class, by which countries, and how the field has evolved over the years. Quantitative Science and Technology Indicators, produced by applying Bibliometrics and Text Mining to scientific papers, can aid in achieving this task. In this work, we evaluated the evolution and distribution of Hydrogen Storage Materials research using this methodology. Papers in the 2000–2015 period were collected from Web of Science and processed in VantagePoint〈sup〉®〈/sup〉 bibliometric software. A thesaurus was elaborated relating keywords and short phrases to specific Hydrogen Storage Materials classes. The number of publications in Hydrogen Storage Materials grew markedly from 2003 to 2010, reducing the pace of growth afterwards until a plateau was reached in 2015. The most researched materials were MOFs, Simple Hydrides and Carbon-based materials. There were three typical trends in materials classes: emerging materials, developed after 2003, such as MOFs and Borohydrides; classical materials with continuous growth during the entire period, such as Simple Hydrides; and stagnant or declining materials, such as Carbon Nanotubes and AB〈sub〉5〈/sub〉 Alloys. The main publishing countries were China, countries from the European Union (EU) and the USA, followed by Japan. There is a division between countries with continued growth in recent years, such as China, and those with stagnant production after 2010, such as the EU, the USA and Japan. The results of this work, compared to a previous study in storage materials patenting by our group, and the recent launch of commercial hydrogen cars and trains and stationary hydrogen production and fuel cell solutions, indicates that although the Hydrogen Energy field as a whole is transitioning from lab and prototype stages to commercial deployment, materials-based hydrogen storage still has base technological challenges to be overcome, and therefore still needs more scientific research before large scale commercialization can be realized. The developed thesaurus is made available for refinement and future works.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 23 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): R.A.R. Ferreira, C.N. Ávila-Neto, F.B. Noronha, C.E. Hori〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liquefied petroleum gas (LPG) is a mixture of hydrocarbons that has a broad distribution network in several countries. In this context, the objective of this study was to evaluate the steam reforming of LPG using catalysts derived from hydrotalcites. The precursors were characterized by X-ray fluorescence analysis, BET surface area, temperature programmed reduction, thermogravimetric analysis, 〈em〉in situ〈/em〉 X-ray diffraction spectroscopy and X-ray absorption spectroscopy. Catalysts were synthesized with 47.5% Ni content without increasing the particle diameter. All catalysts showed the formation of the same gas phase products: H〈sub〉2〈/sub〉, CO, CH〈sub〉4〈/sub〉 and CO〈sub〉2〈/sub〉. Ni〈sub〉1.64〈/sub〉Mg〈sub〉1.36〈/sub〉Al catalyst showed the highest conversion (about 70%) and lower deactivation by coke deposition after 24 h reaction. The use of higher reaction temperatures (1073 and 1173 K), for steam reforming process, resulted in higher conversions of LPG, increased formation of H〈sub〉2〈/sub〉 and lowered the formation of carbon deposits.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Rami S. El-Emam, Ibrahim Dincer, Calin Zamfirescu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nuclear energy is considered a key alternative to overcome the environmental issues caused by fossil fuels. It offers opportunities with an improved operating efficiency and safety for producing power, synthetic fuels, delivering process heat and for multigeneration applications. The high-temperature nuclear reactors, although possess great potential for integration with thermochemical water-splitting cycles for hydrogen production, are not yet commercially established. Current nuclear reactor designs providing heat at relatively low temperature can be utilized to produce hydrogen using thermochemical cycles if the temperature of their thermal heat is increased. In this paper, a hybrid chemical-mechanical heat pump system is proposed for upgrading the heat of the Enhanced CANDU (EC6) reactor design to the quality required for the copper-chlorine (Cu–Cl) hybrid thermochemical water splitting cycle operating at 550–600 °C. A modification to the heat pump is proposed to bring the heat to temperature higher than 650 °C with operating coefficient of performance estimated as 0.65.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Yong Zhang, Guangwu Wen, Shan Fan, Wenhui Ma, Shuhua Li, Tao Wu, Zhaochuan Yu, Baoru Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉At present, amino acids are often used as the source of heteroatom functional groups for the preparation of doped graphene materials. However, a large amount of amino acids will be used as reaction precursors in the preparation process, which will lead to increased cost, reduced efficiency and waste of resources. Herein, a very small amount of neutral 〈span〉l〈/span〉-alanine is employed to synthesize 3D carboxyl and hydroxyl co-enriched graphene hydrogels (CHGHs) by a one-pot hydrothermal method. The CHGHs contain copious carboxyl and hydroxyl groups, and a small amount of nitrogen-containing functional groups. In addition, the CHGHs also present large specific surface areas and 3D porous structures. Therefore, the CHGH-20 binder-free electrode displays a high specific capacitance of 262.8 F g〈sup〉−1〈/sup〉 at 0.3 A g〈sup〉−1〈/sup〉, and this value still maintains 84.3% (221.6 F g〈sup〉−1〈/sup〉) at 10 A g〈sup〉−1〈/sup〉 in a two-electrode system in 6 M KOH. Furthermore, the CHGH-20 electrode also displays outstanding cycle stability with 103.6% of its initial capacitance after 10,000 cycles at 10 Ag〈sup〉−1〈/sup〉. Therefore, the CHGHs samples prepared by a very small amount of neutral 〈span〉l〈/span〉-alanine have great significance for the practical application of supercapacitors.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919325935-fx1.jpg" width="281" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Shitanshu Sapre, Kapil Pareek, Rupesh Rohan, Pawan Kumar Singh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrogen as compressed gas is a promising option for zero-emission fuel cell vehicle. The fast and efficient refueling of high pressure hydrogen can provide a convenient platform for fuel cell vehicles to compete with conventional gasoline vehicles. This paper reports the finding of adiabatic simulation of the refueling process for Type IV tank at nominal working pressure of 70 MPa with considering the station refueling conditions. The overall heat transfer involved in refueling process was investigated by heat capacity model based on MC method defined by SAE J2601. The simulation results are validated against experimental data of European Commission's Gas Tank Testing Facility at Joint Research Centre (GasTef JRC), Netherlands. The results confirmed that end temperature and state of charge significantly depends on refueling parameters mainly supply hydrogen temperature and filling rate.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Ekaterina A. Kozlova, Evgenii N. Gribov, Anna Yu. Kurenkova, Svetlana V. Cherepanova, Evgeny Yu. Gerasimov, Denis V. Kozlov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel composite photocatalysts consisting of a cadmium and zinc sulfide solid solution (Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S) and zinc sulfide (ZnS) nanoparticles were successfully prepared by a simple hydrothermal treatment of suspended Cd〈sub〉0.3〈/sub〉Zn〈sub〉0.7〈/sub〉S at 120 °C. The as-obtained materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and UV-VIS diffuse reflection spectroscopy. The obtained photocatalysts were tested in the photocatalytic evolution of hydrogen from a Na〈sub〉2〈/sub〉S/Na〈sub〉2〈/sub〉SO〈sub〉3〈/sub〉 aqueous solution under visible light irradiation (λ = 450 nm). It is shown that the hydrothermal treatment of Cd〈sub〉0.3〈/sub〉Zn〈sub〉0.7〈/sub〉S at 120 °C increases the activity by a factor of 7.5 due to the phase transformations of the solid solution with the formation of the multiphase Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S/ZnS sample. The deposition of gold on the surface of Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S/ZnS leads to a further increase in activity: the achieved photocatalytic activity and quantum efficiency (450 nm) for 1%Au/Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S/ZnS are 17.4 mmol g〈sup〉−1〈/sup〉 h〈sup〉−1〈/sup〉 and 42.6%, respectively. This excellent performance is found to be attributable to the transformation of Cd〈sub〉1-x〈/sub〉Zn〈sub〉x〈/sub〉S from the cubic to the hexagonal phase during the hydrothermal treatment. Additionally, photoelectrodes based on Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S/ZnS and FTO were synthesized and tested in a two-electrode cell. A high value of the photocurrent equal to 0.5 mA/cm〈sup〉2〈/sup〉 is achieved for the Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S/ZnS/FTO electrode. An investigation by means of impedance spectroscopy reveals the longer lifetime of photogenerated charge carriers in the Cd〈sub〉0.6〈/sub〉Zn〈sub〉0.4〈/sub〉S/ZnS/FTO photoelectrode if to compare with Cd〈sub〉0.3〈/sub〉Zn〈sub〉0.7〈/sub〉S/FTO system.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919326369-fx1.jpg" width="215" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 22 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): M. Garara, H. Benzidi, M. Lakhal, M. Louilidi, H. Ez-Zahraouy, A. El Kenz, M. Hamedoun, A. Benyoussef, A. Kara, O. Mounkachi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Owing to the existence of periodic channels in phosphorene, this 2D material can be a good candidate for room temperature reversible hydrogen storage. The density functional theory calculations (DFT), including van der Waals interactions (vdW-DF2) coupled with the cooper exchange functional (C09), has been applied to study the potential of phosphorene as a new 2D material for hydrogen storage. Our results show that the adsorption energy (−292 to −277 meV) of H〈sub〉2〈/sub〉 on phosphorene is appropriate for storage. The analysis of diffusion pathways between different physisorbed states on phosphorene shows that a single hydrogen molecule diffuses very easily along the open channel (less than 1 meV along the zigzag direction), as compared to 14 meV for diffusion across the channels (along the armchair direction). The potential energy surfaces for the dissociative chemisorption of H〈sub〉2〈/sub〉 was computed on highly symmetric sites of phosphorene and the highest activation barrier was found to be 2.77 eV. The very large dissociation energy coupled with a strong physisorption of H〈sub〉2〈/sub〉 on phosphorene and facile diffusion, makes this 2D material a promising candidate for H〈sub〉2〈/sub〉 storage at room temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 10 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): M.S. Yahya, N.A. Ali, N.A. Sazelee, N.S. Mustafa, F.A. Halim Yap, M. Ismail〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Notable effects of Li〈sub〉3〈/sub〉AlH〈sub〉6〈/sub〉 on the hydrogen storage properties of the NaBH〈sub〉4〈/sub〉 are studied intensively. Li〈sub〉3〈/sub〉AlH〈sub〉6〈/sub〉 is synthesized by milling 2LiH-LiAlH〈sub〉4〈/sub〉 mixture for 12 h. The best molar ratio of the NaBH〈sub〉4〈/sub〉- Li〈sub〉3〈/sub〉AlH〈sub〉6〈/sub〉 destabilized system is 1:1 which has decomposed at two stages; Li〈sub〉3〈/sub〉AlH〈sub〉6〈/sub〉 decomposition stage at 170 °C and NaBH〈sub〉4〈/sub〉decomposition stage at 400 °C. As no significant effect on the decomposition temperature between 1 h and 24 h of milling time can be observed, the 1-hour milling preparation method is selected for the characterization. Isothermal absorption has shown that the system is able to absorb 4.2 wt% and 6.1 wt% of hydrogen in 60 min at 330 °C and 420 °C under 30 atm of hydrogen pressure. In contrast, only about 3.4 wt% and 3.7 wt% of hydrogen can be absorbed by the milled NaBH〈sub〉4〈/sub〉 under a similar condition. Meanwhile, the system is able to desorb 2.0 wt% and 4.1 wt% of hydrogen in 60 min at 330 °C and 420 °C in isothermal desorption while only 0.3 wt% and 2.1 wt% can be released by the milled NaBH〈sub〉4〈/sub〉 under the similar condition. The decomposition activation energy and enthalpy of the NaBH〈sub〉4〈/sub〉 stage are calculated to be 162.1 kJ/mol and 68.1 kJ/mol H〈sub〉2〈/sub〉. Based on the X-ray diffraction analysis, Na, Al and AlB〈sub〉2〈/sub〉 are formed during the dehydrogenation process. The formation of Al and AlB2 are the keys to the improvement of hydrogenation properties. It is concluded that Li〈sub〉3〈/sub〉AlH〈sub〉6〈/sub〉 is a good destabilizing agent for the NaBH〈sub〉4〈/sub〉 system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 9 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Igor Milanović, Nikola Biliškov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work reports a new procedure for solid state synthesis of sodium amidoborane (NaAB) by mechanochemical (MC) reaction between as-received NaH and MC pretreated AB. Ball milling (BM) method was used for this purpose. First, pretreated AB was obtained by BM of as-received AB for 4.5 min. Second, powder of pretreated AB was mixed with as-received NaH and conducted to BM. Milling times were from 0 to 200 min: 5, 10, 30, 50, 100 and 200 min, respectively. By fixing the parameters of the milling conditions, only the influence of milling time on NaAB formation was followed. FTIR and XRD methods are used for analysis of powders after milling. We proved, by MC modification of pure AB, that the reaction rate between AB and NaH could be restricted to the interface between newly formed larger AB and small NaH particles. In such a way we obtained much better control of the reaction system with very accurate determination of reaction steps. Depending on the milling times, reaction process can be separated in three phases: i) 0–30 min phase - reactant and product are present; ii) 50–100 min phase - formed NaAB is almost without other pure; iii) 200 min phase - NaAB is totally decomposed. By this synthesis procedure we produced, for the first time, pure NaAB almost without any impurities.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919322530-fx1.jpg" width="296" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 23 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Motomichi Koyama, Daisuke Yamasaki, Arisa Ikeda, Tomohiko Hojo, Eiji Akiyama, Kenichi Takai, Kaneaki Tsuzaki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of martensitic transformation on microstructural hydrogen distribution in a multiphase transformation-induced plasticity (TRIP) steel were investigated using silver decoration before and after cooling and cryogenic thermal desorption spectroscopy (C-TDS) during cooling. Transformation-induced hydrogen effusion occurred; however, there was a significant difference between the temperature of the peak hydrogen desorption rate and the start temperature of the martensitic transformation, in contrast to the findings of a previous study on fully austenitic steels. Furthermore, the silver-decoration experiment clarified that martensitic transformation caused a significant increase in local hydrogen flux and accordingly enhanced the heterogeneity of the hydrogen distribution, which originates from the transformation-induced hydrogen effusion observed in the C-TDS analysis.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Duan Congwen, Cao Yizheng, Hu Lianxi, Zhang Yuling, Fu Dong, Ma Jinlong, Zhang Jinghong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mechanochemical activation-assisted synthesis, compared to conventional wet methods, exhibits advantages such as higher chemical homogeneity and better quality of the resulting nano-crystals, in preparing nano-sized aluminum hydride (AlH〈sub〉3〈/sub〉). Solid/liquid state milling is effective and convenient for production of 〈em〉α〈/em〉〈strong〉-〈/strong〉AlH〈sub〉3〈/sub〉/LiCl nano-composites through a mechanochemical reaction of LiH and AlCl〈sub〉3〈/sub〉 in [2-Eim] OAc. However, the kinetics of this process has not been thoroughly studied. In this work, we studied the kinetics of mechanochemical synthesis of 〈em〉α〈/em〉〈strong〉-〈/strong〉AlH〈sub〉3〈/sub〉/LiCl nano-composite to understand the reaction process and find the optimum milling parameters (including shortest time to achieve high-quality product). We performed isothermal desorption tests for as-milled samples at 80 °C. Structures of the products were analyzed using X-ray powder diffraction. Johnson-Mehl-Avrami (JMA) model was adopted to describe the process, which contains transformation fraction and chemical reaction controlled regime. Kinetics of mechanochemical reaction at the beginning was limited by diffusion rate of the reagent, and later controlled by nucleation of AlH〈sub〉3〈/sub〉. By fitting the experimental data, apparent activation energy for the mechanochemical reaction was calculated as 39.6 kJ/mol.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Jiping Ding, Yuanfang Cheng, Chuanliang Yan, Bengjian Song, Hao Sun, Fei Teng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gas hydrate is considered to be one of the most promising energy sources of the 21st century, however, with the deepening of research on hydrate resources and the acceleration of trial exploitation processes, it has become apparent that sand production is one of the key factors restricting hydrate exploitation. Here we focus on the key issues of sand production in natural gas hydrate reservoirs in the Liwan Sea area in the northern part of the South China Sea. Innovative systematic studies of the mode of hydrate sand production using a multi-channel hydration acoustic wave monitoring system were conducted. The results show that a hydrate formation composed of very fine silt is prone to excessive sand production requirement. When the production pressure difference is only 1 MPa, the sand output already accounts for 19% of total liquid production, making sand production an important issue under these conditions. Finally, using filter screens with different pore sizes, hydrate reservoir sand control simulations were carried out. The results were analysed to determine properties such as: sand yield, permeability, sand content, and productivity. The design criterion for the filter screen of the fine sand particles in hydrate formations was finally obtained as 〈em〉D〈/em〉〈sub〉50〈/sub〉 = 11〈em〉d〈/em〉〈sub〉50〈/sub〉 (where 〈em〉D〈/em〉〈sub〉50〈/sub〉 is median grain size of the gravel, and 〈em〉d〈/em〉〈sub〉50〈/sub〉 is the median grain size of the formation).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 23 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): C. Xu, Q.A. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High purity Ta〈sub〉2〈/sub〉C was successfully prepared and the hydrogen absorption−desorption kinetic properties of MgH〈sub〉2〈/sub〉−10 wt% Ta〈sub〉2〈/sub〉C composites were investigated systematically. It was found that the hydrogen absorption of Mg−10 wt% Ta〈sub〉2〈/sub〉C (20 nm) composite takes about 5 min to reach saturation at 573 K, and its hydride fully desorbs hydrogen within 15 min at 623 K. These kinetic properties are much better than those of the undoped Mg and MgH〈sub〉2〈/sub〉 prepared under the same condition, respectively. The improvement in the hydrogen storage kinetics is ascribed to the catalytic effect of Ta〈sub〉2〈/sub〉C and its inhibition role in crystallite growth.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Toshihiro Takashima, Tsugeru Sano, Hiroshi Irie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a photocatalyst for solar water splitting, niobium-substituted silver tantalate (AgTa〈sub〉0.7〈/sub〉Nb〈sub〉0.3〈/sub〉O〈sub〉3〈/sub〉) modified with platinum (Pt) and cobalt phosphate (Co–Pi) was synthesized by a combination of hydrothermal synthesis and photodeposition. Under simulated solar light, AgTa〈sub〉0.7〈/sub〉Nb〈sub〉0.3〈/sub〉O〈sub〉3〈/sub〉 could split water into hydrogen and oxygen in a stoichiometric ratio, and enhancement of the reaction rate owing to the cocatalyst deposition was observed. In particular, co-loading of Pt and Co–Pi considerably enhanced the photocatalytic activity, whereas the enhancement was moderate when either was loaded alone. A possible mechanism for the enhancement is explained based on the band position of AgTa〈sub〉0.7〈/sub〉Nb〈sub〉0.3〈/sub〉O〈sub〉3〈/sub〉 against redox potentials for hydrogen and oxygen evolution.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919326321-fx1.jpg" width="371" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Prerna Tiwari, George Tsekouras, Klaudia Wagner, Gerhard F. Swiegers, Gordon G. Wallace〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new class of ‘〈em〉bubble-free〈/em〉’ alkaline electrolyzer with electrodes comprising of PTFE-based Gortex gas diffusion layers coated with catalysts, is described (PTFE = poly(tetrafluoroethylene)). At ≥80 °C (E〈sup〉o〈/sup〉〈sub〉cell〈/sub〉 1.18 V), the electrolyzers displayed the lowest cell onset potentials (≥1.28 V) yet reported, indicating that they exhibit the highest-known intrinsic efficiency when the influence of impedance is stripped out. The overpotentials at each electrode, particularly the oxygen-generating anode, were significantly diminished by the presence of the porous Gortex substrate, which exhibited a powerful ‘〈em〉gas-philic’〈/em〉 capillary action (6.3 bar capillary pressure). The bubble-free process arose from preferential coalescence of newly-formed gases on the PTFE surfaces, where the capillary action of the Gortex continuously extracted them before they could nucleate bubbles. In so doing, observable bubble formation was avoided, along with the energy penalties associated with the formation and release of gas bubbles.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 22 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Luiz F. Kremer, Rogério J. Baierle〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉First-principles calculations within the density functional theory (DFT) have been addressed to investigate the energetic stability, electronic and optical properties of graphene and silicene nanodomains in a SiC single layer (h-SiC). We observe that graphene domains form a planar structure and give rise to an occupied and an empty electronic levels inside the h-SiC band gap, leading the h-SiC to present a strong optical absorption peak in the visible region. On the other hand, when a silicene nanodomain is present the system is no longer planar and present a corrugated structure similar to the silicene structure. The silicene nanodomain introduce three empty electronic levels within the band gap, leading the h-SiC with optical absorption in the visible region. These results show that a graphene nanodomain in h-SiC is appropriate for optical devices, while silicene nanodomains form almost sp〈sup〉3〈/sup〉 quantum dots. This finding suggest that the graphene and silicene nanodomains in a SiC single layer increase the possibility to use h-SiC to produce new electronic and optical devices as well for energy storage by hydrogen adsorption. In fact, we study the H〈sub〉2〈/sub〉 and O〈sub〉2〈/sub〉 adsorption on the pristine system and on the nanodomains, we observe that the presence of the nanodomais increase the binding energies of the adsorbed molecules.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919328812-fx1.jpg" width="420" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 21 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Ziqian Gao, Longlong Wang, Lei Wang, Jingwei Huang, Houde She, Qizhao Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Construction of heterostructured photocatalysts is a feasible method for improving hydrogen production from water splitting because of its good charge transport efficiency. Herein, we coupled the Ti-MOFs (TiATA) with metal-free graphitic carbon nitride (g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) to synthesize composites, g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉@TiATA, in which a heterostructure was formed between g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and TiATA. The establishment of heterojunctions not only broadens the light absorption range of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉@TiATA (490 nm) by contrast with g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 (456 nm), but also greatly accelerates charge migration. Photocatalytic studies present that the construction of heterostructure steering the charges flow from g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 to TiATA and then delivery to the cocatalyst of Pt nanoparticles, exhibiting an impressively photocatalytic hydrogen production rate (265.8 μmol·h〈sup〉−1〈/sup〉) in assistance of 300 W Xenon lamp, which is about 3.4 times as much as g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Pt.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉We used an applicable synthetic method to prepare a composite by introducing a heterostructure into g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉@MOFs and present ameliorated photocatalytic hydrogen production.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919328472-fx1.jpg" width="343" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Kan-Rong Lee, Chung-Jen Tseng, Shian-Ching Jang, Jing-Chie Lin, Kuan-Wen Wang, Jeng-Kuei Chang, Ting-Chia Chen, Sheng-Wei Lee〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A thin and fully dense BaCe〈sub〉0.6〈/sub〉Zr〈sub〉0.2〈/sub〉Y〈sub〉0.2〈/sub〉O〈sub〉3-δ〈/sub〉 (BCZY) electrolyte for the use of anode-supported protonic fuel cells has been successfully prepared by spin coating using NiO sintering aid. The effects of NiO addition on the electrolyte microstructures and fuel cell performances are also investigated. An appropriate NiO addition has a significant positive contribution to the densification and grain growth of thin BCZY electrolytes. However, too much NiO addition gives rise to NiO aggregation in BCZY electrolyte and deteriorates the cell performance. The enhanced sintering mechanism can be mainly attributed to the oxygen vacancies generated from the NiO decomposition and bulk diffusion of Ni into BCZY perovskites. The fuel cell with a BCZY-3%NiO electrolyte exhibits the highest maximum power density of ~106.6 mW/cm〈sup〉2〈/sup〉 at 800 °C among all fuel cells in this study. The electrochemical impedance characteristics of thin BCZY electrolyte fuel cells are further discussed under open circuit conditions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919326722-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Bo Shi, Xinqi Han, Xingquan He, Lili Cui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is well proved that fabricating more defects on basal plane of layered double hydroxides (LDHs) is one of effective ways to boost the electrocatalytic performance for oxygen evolution reaction (OER). For the first time, the nickel iron LDHs (NiFe LDHs) with hierarchical morphology and abundant defects are simultaneously constructed by one-step electrodeposition (ED) strategy with easy operation, time-saving and green chemistry. Remarkably, the morphology is elaborately tailored by changing the species of doped anions which is unique. Also, the X-ray photoelectron spectroscopy (XPS) results elucidate that the Fe sites are in electron-rich state in LDHs which is revealed to enhance the catalytic activity strongly arising from the generation of oxygen vacancy. To deliver the current density of 10 mA cm〈sup〉−2〈/sup〉, the optimal NiFe LDHs require the overpotential of 128, 106 mV for OER and hydrogen evolution reaction (HER), and achieve 100 mA cm〈sup〉−2〈/sup〉 at the overpotential of 237, 242 mV, respectively. As a bifunctional electrocatalyst, the NiFe LDHs exhibit the current density of 10 mA cm〈sup〉−2〈/sup〉 at a cell voltage of 1.55 V and 100 mA cm〈sup〉−2〈/sup〉 at 1.76 V, which are lower than that of most of benchmarking materials reported previously.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919326576-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Daniel Fernández-Galisteo, Eduardo Fernández-Tarrazo, Carmen Jiménez, Vadim N. Kurdyumov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In an effort to investigate the suitability of the concept of portable hydrogen production, we examine numerically the combustion of a very rich methanol-air mixture in a micro-gap assembly consisting of multiple counter-current channels of finite length separated by thin solid conducting walls. Within the mathematical framework of the narrow-channel approximation, the problem can be formulated as a one-dimensional model for a single channel with an extra term representing heat transfer from the hot stream products to the fresh reactants in adjacent channels. We show that the heat recirculation enables superadiabatic temperatures inside the reactor and promotes the oxidation of methanol far beyond the conventional rich limit of flammability. The result is a feasible thermal partial oxidation that produces hydrogen without the need for a catalyst. The paper presents an analysis of the model burner performance with detailed gas-phase kinetics in stationary regimes in terms of operating variables such as the equivalence ratio and the gas inflow velocity, and in terms of physical parameters such as the length of the reformer and the conductivity of the wall material. The idealized microreactor predicts maximum hydrogen yield of the order of 60% at equivalence ratios between 3 and 6.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Ping Li, Qiangling Duan, Qian Zeng, Kaiqiang Jin, Jiayan Chen, Jinhua Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The shock wave dynamics, spontaneous ignition and flame variation during high-pressure hydrogen release through tubes with different cross-section shapes are experimentally studied. Tubes with square, pentagon and circular cross-section shapes are considered in the experiments. The experimental results show that the cross-section shape of the tube has no great difference on the minimum burst pressure for spontaneous ignition in our tests. In the three tubes with length of 300 mm, spontaneous ignition may occur when overpressure of shock wave is 0.9 MPa. When the spontaneous ignition is induced in a non-circular cross-section tube, the possible turbulent flow in the corner of the tube increases can promote the mixing of hydrogen and air, thus producing more amount of the hydrogen/air mixture. As a result, both the peak light signal and flame duration detected in the non-circular cross-section tubes are more intense than those in the circular tube. The smaller angle of the corner leads to a more intensity flame inside tube. When the hydrogen flame propagates to the tube exit from the circular tube, the ball-like flame developed near tube exit is relatively weak. In addition, second flame separation outside the tube is observed for the cases of non-circular cross-section tubes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 9 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 38〈/p〉 〈p〉Author(s): Paola Russo, Alessandra De Marco, Fulvio Parisi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pipelines are the most efficient method of transporting large quantities of hydrogen, and the low volumetric energy density of gaseous hydrogen requires that the gas must be compressed to extremely high pressure to be used as a transport fuel. The failure of high pressure hydrogen gas pipelines and subsequent explosion may induce heavy damage to buildings. In this paper, such an issue is addressed for existing reinforced concrete framed buildings and tuff stone masonry buildings. Physical features such as the gas jet release process, flammable cloud size, blast generation and propagation, and explosion effects on structural components of buildings are considered and evaluated through the SLAB integral model, Multi-Energy Method and pressure‒impulse diagrams. Damage to both types of structural components was evaluated and the maximum distance of blast damage was derived in several environmental conditions, contributing to land-use planning and performance-based design/assessment of pipelines and buildings.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Neda Esmaeili, Pourya Mohammadi, Mehdi Abbaszadeh, Hassan Sheibani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present research, magnetically recyclable graphene oxide (GO)/dopamine hydrochloride/AuNPs nanocatalyst are prepared by a green path with 〈em〉Acorus calamus〈/em〉 seeds extract as a stabilizing and reducing agent and its catalytic efficiency was used for the reduction of methylene blue (MB) and methyl orange (MO) in the presence of NaBH〈sub〉4〈/sub〉 as a reducing agent in the aqueous medium in the ambient conditions. The prepared nanocatalyst was characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), Fourier transformed infrared (FT-IR) spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and UV–Vis spectroscopy. The prepared nanocatalyst has good catalytic activity and can be regain by an external magnet and recycled several times without considerable loss of its catalytic activity in the process of reduction of organic dyes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Sai Liu, Xin Chen, Zhou-Jie Wu, Xiu-Cheng Zheng, Zhi-Kun Peng, Pu Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hybrids consisting of chitosan (CS) and reduced graphene oxide (rGO) were assembled with an 〈em〉in-situ〈/em〉 reduction strategy. Then, the resulting CS-rGO was used to encapsulate palladium nanoparticles (Pd NPs) via reducing PdCl〈sub〉2〈/sub〉 with NaBH〈sub〉4〈/sub〉. The mass ratios of CS to GO were optimized to increase the catalytic activity of the resultant Pd NPs/CS-rGO catalysts for the hydrolysis of ammonia borane (AB). The analytic results revealed that the Pd NPs (1.1–2.3 nm in diameter) were evenly encapsulated in the CS-rGO hybrids. Under the present conditions, the optimized Pd NPs/CS-rGO offered a high turnover frequency (TOF) value of 42.5 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mi〉m〈/mi〉〈mi〉o〈/mi〉〈msub〉〈mrow〉〈mi〉l〈/mi〉〈/mrow〉〈mrow〉〈msub〉〈mrow〉〈mi〉H〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/msub〉〈mi〉m〈/mi〉〈mi〉o〈/mi〉〈msubsup〉〈mrow〉〈mi〉l〈/mi〉〈/mrow〉〈mrow〉〈mi〉P〈/mi〉〈mi〉d〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈/mrow〉〈/msubsup〉〈mspace width="0.25em"〉〈/mspace〉〈mi〉m〈/mi〉〈mi〉i〈/mi〉〈msup〉〈mrow〉〈mi〉n〈/mi〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉. The activation energy of the AB hydrolysis was 39.02 kJ mol〈sup〉−1〈/sup〉 and the corresponding orders of Pd and AB concentrations were 0.90 and 0.33, respectively. In addition, the Pd NPs/CS-rGO catalysts retain a stable hydrogen generation activity after four runs.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919326631-fx1.jpg" width="295" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 3 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 42〈/p〉 〈p〉Author(s): Kaifeng Wang, Qi Wu, Xiaoming Yan, Jiafei Liu, Li Gao, Lei Hu, Ning Zhang, Yu Pan, Wenji Zheng, Gaohong He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High-performance anion exchange membranes (AEMs) are in need for practical application of AEM fuel cells. Novel branched poly(ether ether ketone) (BPEEK) based AEMs were prepared by the copolymerization of phloroglucinol, methylhydroquinone and 4,4′-difluorobenzophenone and following functionalization. The effects of the branched polymer structures and functional groups on the membrane's properties were investigated. The swelling ratios of all the membranes were kept below 15% at room temperature and had good dimensional stability at elevated temperatures. The branching degree has almost no effect on the dimensional change, but plays a great role in tuning the nanophase separation structure. The cyclic ammonium functionalized membrane showed a lower conductivity but a much better stability than imidazolium one. The BPEEK-3-Pip-53 membrane with the branching degree of 3% and piperidine functionalization degree of 53% showed the best performances. The ionic conductivity was 43 mS cm〈sup〉−1〈/sup〉 at 60 °C. The ionic conductivity in 1 M KOH at 60 °C after 336 h was 75% of its initial value (25% loss of conductivity), and the IEC was 83% of its initial value (17% loss of IEC), suggesting good alkaline stability. The peak energy density (60 °C) of the single H〈sub〉2〈/sub〉/O〈sub〉2〈/sub〉 fuel cell with BPEEK-3-Pip-53 membrane reached 133 mW cm〈sup〉−2〈/sup〉 at 260 mA cm〈sup〉−2〈/sup〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Junfang Ding, Liping Li, Ye Wang, Xianzhe Xu, Shaoqing Chen, Xiyang Wang, Huixia Li, Shuaiqiang Zhao, Guangshe Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Precious metal nanoparticles, widely used as heterogeneous catalysts, are easy to aggregate and deactivate, restricting their applications in many important catalytic fields like preferential CO oxidation (CO-PROX) in H〈sub〉2〈/sub〉-rich stream. In this work, well dispersed Rh nanoclusters anchored on CaCO〈sub〉3〈/sub〉@biocarbon derived from waste eggshell (ESMC) were synthesized through a step carbonization and incipient wetness impregnation process. The obtained catalysts exhibited 3D macroporous architecture, which is favorable for exposure of more nucleation sites of precious metal Rh, thus minimizing the aggregation of Rh particles. Furthermore, a thick carbon shell attached to eggshells, with interesting electronic structure and surface chemistry, efficiently transfers electrons between Rh and biocarbon@CaCO〈sub〉3〈/sub〉 support, and enhances the interaction between Rh NPs and support. Both effects synergistically allow Rh/ESMC to equip more active adsorption sites-asymmetric Rh(CO)〈sub〉2〈/sub〉 gem-dicarbonyl, thus greatly promoting the catalytic performance of Rh/ESMC in CO-PROX (operation temperature window: 140–240 °C). The present finding offers an environmentally friendly approach to fabricate well dispersed Rh nanoclusters catalysts, and it can be extended to rationally design other supported metal nanoparticle catalysts.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919325911-fx1.jpg" width="291" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Ali Malekian, Sina Salari, Juergen Stumper, Ned Djilali, Majid Bahrami〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, effects of compression (up to 5 MPa) on pore size distribution (PSD) and porosity of catalyst layers (CL) are investigated using a developed model for deformation of CL under compression. The model is based on effective medium theory and uses a representative geometry (unit cell) to simplify the complex and random porous structure of CL. In this model, different sizes are found for unit cells which are based on CL PSD measurement; this means that unit cell size has distribution since PSD is used as an input to the model. The model has been validated with experimental data in our previous publications. Effect of compression on four different CL samples is studied using the developed model and change of pore diameter is found as function of compression. The change of pore size is different for each sample and dependents on CL initial porosity, PSD, and ink properties. PSD and porosity, which are the indications of microstructure of CL, are found after compression up to 5 MPa. Larger pores show the most change, which causes the void volume percentage of smaller pores to increase, even though the number of pores remain the same. It is also found that the diameter of secondary pores can be decreased by up to 50% depending on CL microstructure, which is significant.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 1 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Marc Novelli, Kaveh Edalati, Shota Itano, Hai-Wen Li, Etsuo Akiba, Zenji Horita, Thierry Grosdidier〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Structural observations were carried out on particles obtained after hydrogenation cycling of the Ti〈sub〉25〈/sub〉V〈sub〉50〈/sub〉Cr〈sub〉25〈/sub〉 and Ti〈sub〉10〈/sub〉V〈sub〉75〈/sub〉Cr〈sub〉15〈/sub〉 alloys processed by surface or bulk severe plastic deformation using the surface mechanical attrition treatment (SMAT) and high-pressure torsion (HPT) techniques, respectively. The produced particles differ in morphologies and fracture mode due to the differences in hydrogen diffusion paths. The fracture mode for the SMAT-processed samples with the gradient microstructure was mainly intragranular, whereas it was intergranular for the nanograined HPT processed samples. Hydrogen diffusion, which initiated at the grain boundaries on the surface, created Ti-rich and V-lean areas. The powders contained mainly β-VH monohydride and partly γ-VH〈sub〉2〈/sub〉 dihydride, and an orientation relationship of (100)〈sub〉β〈/sub〉//(110)〈sub〉γ〈/sub〉 and [001]〈sub〉β〈/sub〉//[001]〈sub〉γ〈/sub〉 with an angular deviation of ∼2.5° was observed between the two phases using the electron backscattered diffraction (EBSD) analysis.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 31 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): M. Batouche, T. Seddik, Tuan V. Vu, Dat D. Vo, Hien D. Tong, D.M. Hoat, O.Y. Khyzhun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Both ternary sulfides, BaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 and CaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉, are found to possess a suitable band gap for absorbing visual light; moreover, the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉E〈/mi〉〈/mrow〉〈mrow〉〈mi〉C〈/mi〉〈mi〉B〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉E〈/mi〉〈/mrow〉〈mrow〉〈mi〉V〈/mi〉〈mi〉B〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 are at right positions allowing the photo-generated electron/hole pairs to split water. The valence band of BaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 (CaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉) are characterized by high peaks at −1 eV and −2 eV, and strong hybridization of S/La-〈em〉p〈/em〉 and Ba-〈em〉s〈/em〉 (Ca-〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈mrow〉〈mi〉s〈/mi〉〈mo linebreak="badbreak"〉/〈/mo〉〈mi〉p〈/mi〉〈/mrow〉〈/math〉) states. These features help to enhance the separation of electron/hole pairs. Meanwhile, the conduction band has high peak at 3 eV, which is mostly constructed by hybridization of La-〈em〉f〈/em〉, La-〈em〉d〈/em〉 and Ba-〈em〉s〈/em〉 (Ca-〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈mrow〉〈mi〉s〈/mi〉〈mo linebreak="badbreak"〉/〈/mo〉〈mi〉p〈/mi〉〈/mrow〉〈/math〉) states. The conduction band's smooth dispersion is favorable for inter-band transition, thus it enhances the absorption rate of two considered compounds. The Ba/Ca/La–S bonds are predominantly covalent with electronegativity difference of about 31–38%. The large difference in effective mass between electron and hole enhances the separation of electron/hole pairs. CaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 and BaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 are p-type semiconductors with positive thermopower 〈em〉S〈/em〉 of about 229.8 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈mrow〉〈mi〉μ〈/mi〉〈mi〉V〈/mi〉〈mo linebreak="badbreak"〉/〈/mo〉〈mi〉K〈/mi〉〈/mrow〉〈/math〉 and 234.8 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈mrow〉〈mi〉μ〈/mi〉〈mi〉V〈/mi〉〈mo linebreak="badbreak"〉/〈/mo〉〈mi〉K〈/mi〉〈/mrow〉〈/math〉, respectively, at Fermi level (μ = 0) and temperature 300 K. Both materials show good thermoelectric performance for hole concentration being in the range 1 × 10〈sup〉19〈/sup〉–1x10〈sup〉21〈/sup〉 cm〈sup〉-3〈/sup〉. The electronic figure of merit 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.svg"〉〈mrow〉〈mi〉Z〈/mi〉〈msub〉〈mrow〉〈mi〉T〈/mi〉〈/mrow〉〈mrow〉〈mi〉e〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 marks the highest value of about 0.95 and 0.97 at 2 × 10〈sup〉19〈/sup〉 cm〈sup〉-3〈/sup〉 for CaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 and BaLa〈sub〉2〈/sub〉S〈sub〉4〈/sub〉, respectively.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919323973-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Ali Djerioui, Azeddine Houari, Samir Zeghlache, Abdelhakim Saim, Mohamed Fouad Benkhoris, Tedjani Mesbahi, Mohamed Machmoum〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper addresses the management of a Fuel Cell (FC) – Supercapacitor (SC) hybrid power source for Electric Vehicle (EV) applications. The FC presents the main energy source and it is sustained with SCs energy storages in order to increase the FC source lifespan by mitigating harmful current transients. For this aim, the reported work proposes a Grey Wolf Optimizer (GWO) for an efficient power management of the studied hybrid power system. The key idea of the proposed approach is to incorporate the benefit of the GWO in terms of fast optimization and convergence accuracy, in order to achieve efficient energy sources exploitation and provide the desired driving performances. Simulations and experimental results verify the validity of the proposed management algorithm.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Paramita Banerjee, Ranjit Thapa, A. Rajkamal, K.R.S. Chandrakumar, G.P. Das〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Presence of curvature is considered as a tuning parameter to activate the hydrogen storage capability of carbon nanostructures. Here, we explicate the role of ‘intra-curvature’ in a set of single-walled carbon nanohorns (SWCNHs), to adsorb light metal ad-atoms (M) e.g. Li, Na, Ca and subsequently explore the metal-doped systems for hydrogen storage application using density functional theory. The binding strength of ad-atoms on SWCNHs of different curvature is correlated with the π electron occupancy of the corresponding carbon ring. Higher π electron occupancy causes significantly high binding energy of the metal ad-atoms (M), thereby indicating high stability of those M−C bonds for intra-curvature values more than 11⁰, even at a higher temperature. After full hydrogenation, Li-doped SWCNHs are found to contain a maximum of 7.5 wt % of hydrogen. Overall, our results indicate that Li-doped SWCNHs with intra-curvature values higher than 11⁰, is a potential candidate for hydrogen storage.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919325327-fx1.jpg" width="469" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Tao Jin, Yuanliang Liu, Jianjian Wei, Dengyang Zhang, Xiaoxue Wang, Gang Lei, Tianxiang Wang, Yuqi Lan, Hong Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Characterization of the dispersion behaviors of spilled liquid hydrogen is necessary from the safety prospective. In this study, the two-phase flow of liquid hydrogen spill is predicted with the mixture multiphase model, Lee model and Realizable 〈em〉k〈/em〉-〈em〉ε〈/em〉 model, and the dispersion of hydrogen vapor cloud with the atmospheric inversion layer is numerically analyzed. The inversion layer restrains the upward movement of the cloud and the mixing of the cloud with air, increasing its ground-level hydrogen concentration. The heights of the flammable cloud can be reduced by 5.71%, 10.49% and 12.86%, respectively, with the temperature lapse rates of 0.03, 0.06 and 0.10 K/m in our investigated scenarios. Besides, the restraining effect is strengthened by increasing the ground air temperature if the temperature lapse rate remains unchanged.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919325236-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Hongbo Tang, Lu Bai, Mingquan Wang, Ye Zhang, Meng Li, Mengxin Wang, Lin Kong, Ning Xu, Yanfeng Zhang, Pinhua Rao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Traditionally, zeolite membranes were prepared using oven heating which usually resulted in lengthy synthesis time and thick membrane. Previous result indicated that oil-bath heating can significantly reduce the synthesis time and membrane thickness of SAPO-34 membrane due to the elimination of thermal-lag. SSZ-13 membrane was prepared using oil-bath heating method. Significant reduction on synthesis time (from 2 to 6 d to 2 h) and membrane thickness (from 5 to 10 μm–1.5 μm) were realized, which is the result of enhanced nucleation and crystallization from ultrafast heat transfer of oil-bath heating. Template removal was realized with an optimized rapid thermal processing method (O-RTP). Outstanding CO〈sub〉2〈/sub〉-CH〈sub〉4〈/sub〉 separation performance was obtained. The high permeance mainly comes from the thinner membrane. The high selectivity can be attributed to O-RTP, which strengthened the bonding between zeolite crystals and minimized thermal exposure time. The combination of oil-bath heating and O-RTP led to high performance SSZ-13 membrane.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Huiming Li, Yang Wang, Wei Zhu, Zhongbin Zhuang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Searching for low-cost electrocatalysts with high activity towards the hydrogen evolution reaction (HER) is of great significance to enable large-scale hydrogen production via water electrolysis. In this study, by using inverse spinel MFe〈sub〉2〈/sub〉O〈sub〉4〈/sub〉(M = Mn, Fe, Co, Cu) nanoparticles (NPs) as the precursors, monodisperse bimetallic phosphide M-Fe-P NPs/C with hollow structures were readily obtained by a gas-solid annealing method. These hollow phosphide NPs displayed excellent HER activity in an acidic medium with a low loading amount of 0.2 mg cm〈sup〉−2〈/sup〉. In particular, the Co–Fe–P NPs/C shows highest HER activity that only requiring an overpotential of 97 mV to retain a current density of 10 mA cm〈sup〉−2〈/sup〉. A volcano relation between activity and incorporated elements was revealed. Incorporation of cation with high electronegativity stabilized the FeP active centres, while phase segregation resulted in the loss of activity for Cu–Fe–P NPs/C.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919325285-fx1.jpg" width="303" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Burak Kurşun, Korhan Ökten〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Concentrated photovoltaic thermal systems (CPV/T) have an important place among solar energy systems because of converting solar energy directly into electrical energy and utilizing waste heat of photovoltaic modules. In the present study, the effect of preheating of the Rankine cycle (RC) heat source (flat plate solar collector) with the CPV/T system on the RC efficiency and hydrogen production was investigated. A theoretical investigation was carried out for different parameters as CPV module aperture area, direct solar radiation, concentration ratio, photovoltaic cell type, mass flow rate and evaporator saturation pressure. Also, the conditions with and without the CPV/T system were compared in terms of system efficiency and hydrogen production. The results of the analysis revealed that the CPV/T system increased energy/exergy efficiencies and hydrogen production at different rates for all parameter values. It was determined that the most important parameters affecting the energy/exergy efficiency and hydrogen production were the CPV module aperture area (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉A〈/mi〉〈/mrow〉〈mrow〉〈mi〉P〈/mi〉〈mi〉V〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉) and the concentrating ratio (〈em〉C〈/em〉). With the use of CPV/T system, an increase in the production of hydrogen in the range of 0.02 kg/h to 0.30 kg/h depending on the parameters was achieved. In addition, exergy destruction rates calculated for the integrated system components and the highest exergy destruction rates were determined to occur in the flat plate solar collector (FPSC) and CPV/T system.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Susumu Takahashi, Hirofumi Sumi, Yoshinobu Fujishiro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gadolinia-doped ceria (GDC) and lanthanum silicate (LS) are expected to be promising materials for electrolytes of solid oxide fuel cells (SOFCs) because of their high ionic conductivities at intermediate temperatures. However, performance degradation of SOFCs is caused by current leakage through GDC and poor densification of LS. In the present study, LS was used as a blocking layer for preventing the current leakage of GDC electrolyte. Thermal shrinkage measurements and scanning electron microscopy (SEM) observation suggested that the addition of Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 in LS electrolyte (LSB) contributed to the decrease in the sintering temperature of the LS and improved densification of the GDC/LS bi-layer electrolyte. Consequently, the open-circuit voltage for the cell with GDC/LS and GDC/LSB bi-layer electrolytes increased effectively in comparison with that of the cell with GDC single-layer electrolyte. The electrical conductivity and fuel cell characteristics were compared among the cells with GDC, GDC/LS, and GDC/LSB electrolytes.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S036031991932525X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Tatiana Lastovina, Andriy Budnyk, Yulia Pimonova, Aram Bugaev, Vladimir Dmitriev〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Heteroatom-doped carbon materials (HDCM) are perspective Pt-free alternatives for applications in fuel cells. The Fe,Co,Zn-N/C catalysts were obtained by pyrolysis (at 700 °C in Ar) of sacrificial bimetallic zeolitic imidazolate frameworks (Co,Zn-ZIF), prepared with different Co/Zn ratio by a microwave-assisted solvothermal synthesis (at 140 °C in DMF for 2 h). Co,Zn-ZIF hybrids were impregnated with a Fe〈sup〉II〈/sup〉-phenanthroline complex before the pyrolysis. The structural properties of prepared materials were assessed primarily by X-ray diffraction (XRD) and transmission electron microscopy (TEM), while X-ray fluorescence (XRF) and the scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (STEM-EDS) mapping and were used for the elemental content analysis. Because in the obtained HDCM both Fe and Co participate in formation of the bamboo-like structures, synchrotron-based X-ray absorption spectroscopy (XAS) studies were performed at their 〈em〉K〈/em〉-edges. The results of 〈em〉in situ〈/em〉 XAS measurements during carbonization of Fe,Co,Zn-ZIF upon heating (up to 500 °C in Ar) as well as 〈em〉operando〈/em〉 XAS measurements during the electrochemical cycling of HDCM are reported. The registered changes in the oxidative state of Fe and Co (XANES) and in their coordinative environment (EXAFS) were analyzed. The study is complemented by the electrochemical tests of the synthesized HDCM (in 0.1 M HClO〈sub〉4〈/sub〉 solution) towards the oxygen reduction reaction, demonstrating their high efficiency and stability in acidic medium.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S036031991932542X-fx1.jpg" width="466" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Kiyotaka Tsunemi, Takehiro Kihara, Etsuko Kato, Akemi Kawamoto, Tei Saburi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A quantitative risk assessment of human life during the operation of a hydrogen refueling station (HRS) is conducted. We calculate the risks for three accident scenarios: a hydrogen leak from the external piping surrounding a dispenser, a hydrogen leak from an accumulator connection piping and a hydrogen leak from a compressor/connection piping in the HRS. We first calculate the probability of accident by multiplying the estimated leak frequency with the incident occurrence probability considering the ignition probability and failure probability of the safety barrier systems obtained through event tree analysis for each scenario. We next simulate the blast and flame effects of the ignition of concentration fields formed by hydrogen leakage. We then use existing probit functions to estimate the consequences of eardrum rupture, fatalities due to displacement by the blast wave, fatalities due to head injuries, first-degree burns, second-degree burns, and fatal burn injuries by accident scenario, leak size, and incident event, and we estimate the risk distribution in 1-m cells. We finally assess the risk reduction effects of barrier placement and the distance to the dispenser and quantify the risk level that HRSs can achieve under existing law. Quantitative risk assessment reveals that the risk for a leak near the dispenser is less than 10〈sup〉−6〈/sup〉 per year outside a distance of 6 m to the dispenser. The risk for a leak near the accumulators and compressors exceeds 10〈sup〉−4〈/sup〉 per year within a distance of 10 m from the ignition point. A separation of 6 m to the dispenser and a barrier height of 3 m keep the fatal risk from burns to the workers, consumers and residents and passersby below the acceptable level of risk. Our results therefore show that current laws sufficiently mitigate the risks posed by HRSs and open up the possibility for a regulatory review.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 30 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy, Volume 44, Issue 41〈/p〉 〈p〉Author(s): Kenji Iwase, Takashi Ueno, Kazuhiro Mori〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An intermetallic compound, La〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉 is synthesized successfully for hydrogen storage, and its crystal structure is determined by X-ray diffraction. The alloy is formed by annealing the precursor at 1073 K for 10 h, and it has a Ce〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉-type structure (space group 〈em〉R〈/em〉-3〈em〉m〈/em〉, 3R) with 〈em〉a〈/em〉 = 0.5130(1) nm and 〈em〉c〈/em〉 = 4.882(1) nm. Its maximum hydrogen capacity reaches 0.92 H/M, but 0.40 H/M of hydrogen remains in the sample after the first desorption. Its reversible hydrogen capacity is 0.51 H/M. The formed hydride phases, phase I (La〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉H〈sub〉10〈/sub〉) and phase II (La〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉H〈sub〉22〈/sub〉) also have the Ce〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉-type crystal structure; the hydride phases retain the same metal sublattice as that of the original alloy. Phase I is formed through anisotropic expansion of the La〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉 lattice, while the unit cell, the MgZn〈sub〉2〈/sub〉-type and CaCu〈sub〉5〈/sub〉-type cells, of phase II is formed by the isotropic expansion of the La〈sub〉5〈/sub〉Co〈sub〉19〈/sub〉 lattice.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Xiaoxia Jia, Muheng Wang, Guang Liu, Yong Wang, Jiangfeng Yang, Jinping Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The exploration of electrocatalysts with high oxygen evolution reaction (OER) activity is highly desirable and remains a significant challenge. Transition metal carbides (TMCs) have been investigated as remarkable hydrogen evolution reaction (HER) electrocatalysts but few used as oxygen evolution reaction (OER) electrocatalysts. Herein, a Co doped Ni〈sub〉3〈/sub〉C/Ni uniformly dispersed in a graphitic carbon matrix was prepared by pyrolysis of a metal organic framework (Co/Ni-MOF) under a flow of Ar/H〈sub〉2〈/sub〉 at 350 °C, and Ni〈sub〉3〈/sub〉C/Ni@C was also prepared for comparison. The various characterization techniques confirmed the successful preparation of the heteroatom doped TMCs-based catalysts by pyrolysis of MOFs. Co doped Ni〈sub〉3〈/sub〉C/Ni@C exhibited superior electrocatalytic properties for OER. For example, Co–Ni〈sub〉3〈/sub〉C/Ni@C depicts a lower overpotential and smaller Tafel slope than Ni〈sub〉3〈/sub〉C/Ni@C and IrO〈sub〉2〈/sub〉 during the OER in 1 M KOH solution, additionally, it shows a higher active surface area than Ni〈sub〉3〈/sub〉C/Ni@C. The outstanding electrocatalytic performance of Co-doped Ni〈sub〉3〈/sub〉C/Ni@C in the OER was mainly ascribed to the synergistic effect of the Co and Ni〈sub〉3〈/sub〉C/Ni active sites.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Franziska Enzmann, Florian Mayer, Dirk Holtmann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In bioelectromethanogenesis, electricity can be converted to methane, partially indirect via electrochemical hydrogen production, partially via direct electron transfer to the electroactive methanogens. The electron transfer mechanism from electrode to methanogens was not fully understood so far. Using a pure culture of 〈em〉Methanococcus maripaludis〈/em〉, we show that the ratio between direct and indirect electron transfer is shifted by altering the process conditions. The largest shift from 95.6% direct to 42.0% indirect electron transfer occurred when reducing the working potential. Further influences were observed by addition of 3-(〈em〉N〈/em〉-morpholino) propanesulfonic acid buffer and alteration of electrode material, but not by alteration of the in-gas composition and gas velocity. In all cases, abiotically produced hydrogen was converted at a high rate of above 75%. This research shows that the electron uptake pathway in bioelectromethanogenesis can be influenced without genetic modifications, offering new possibilities for the examination of the mechanistic behind electroactivity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Huawei Chang, Xiangxiang Xu, Jun Shen, Shuiming Shu, Zhengkai Tu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Proton exchange membrane (PEM) fuel cells produce a large amount of waste heat while generating electricity through electrochemical reactions, making them suitable for driving combined heating and power (CHP) systems. According to the hourly thermal and electric loads in a typical North China household, a 2-kW PEM fuel cell-based micro-CHP system with a lithium-ion battery energy storage system is proposed in this paper. The thermal and economic performances of the micro-CHP system with a lithium-ion battery (CHPWB) and a CHP system without a lithium-ion battery (CHPWOB) are comparatively analyzed by developing a thermal and economic performance analysis model on the MATLAB/Simulink platform. The thermal-load-following strategy is adopted during the design and simulation process. The results indicate that the storage capacity of the lithium-ion battery decreases by 6.6% after one cycle. The lithium-ion battery can be charged by the fuel cell stack during off-peak hours or using commercial electricity, and the charging cycle of the system is one week long. The average total efficiency of the CHPWB system can reach 81.24% with considering the energy loss in each conversion process, which is 11.02% higher than that of the CHPWOB system. The daily hydrogen consumption of the CHPWB system can be reduced by 14.47% compared with the CHPWOB system under the same operating conditions, and the average daily costs can be reduced by 8.4% and 9.5% when the lifespan is 10 and 15 years, respectively.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919327879-fx1.jpg" width="441" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Zequn Chen, Hongfu Jia, Jingrun Yuan, Xi Liu, Chaohe Fang, Yunying Fan, Chuanbao Cao, Zhuo Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To achieve high activity and stability for both hydrogen and oxygen evolution reactions through the non-precious-metal based electrocatalysts is still facing the great challenge. Herein, we demonstrate a facile strategy to prepare CoP nanoparticles (NPs) loaded on N, P dual-doped carbon (NPC) electrocatalysts with high concentration N and P dopants through a pyrolysis-deposition-phosphidation process. The great bifunctional electrocatalytic activity for both HER (the overpotential of 98 mV and 86 mV at 10 mA cm〈sup〉−2〈/sup〉 in both 0.5 M H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 and 1 M KOH electrolytes, respectively) and OER (the overpotential of 300 mV at 10  mA cm〈sup〉−2〈/sup〉 in 1 M KOH electrolyte) were achieved. When CoP@NPC hybrid was used as two electrodes in the 1 M KOH electrolyte system for overall water splitting, the needed cell potential for achieving the current density of 10 mA cm〈sup〉−2〈/sup〉 is 1.6 V, and it also showed superior stability for HER and OER after 10 h’ test with almost negligible decay. Experimental results revealed that the P atoms in CoP were the active sites for HER and the CoP@NPC hybrid showed excellent bifunctional electrocatalytic properties due to the synergistic effects between the high catalytic activity of CoP NPs and NPC, in which the doping of N and P in carbon led to a stronger polarization between Co and P in CoP, promoting the charge transfer from Co to P in CoP, enhancing the catalytic activity of P sites and Co sites in CoP for HER and OER, respectively. Specifically, the improvements could result from the changed charge state, the increased active specific surface area, and the facilitated reaction kinetics by N, P co-doping and admixture. This work provides a high-efficient, low-cost and stable electrocatalyst for overall water splitting, and throws light on rational designing high performance electrocatalysts.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉N, P codoping significantly enhances the catalytic performances of CoP/C nanosheets for both hydrogen and oxygen evolution reactions.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0360319919327892-fx1.jpg" width="432" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Sumithra Sivadas Menon, B. Kuppulingam, K. Baskar, T.N. Sairam, T.R. Ravindran, Bhavana Gupta, Shubra Singh〈/p〉

Description: 〈p〉Publication date: Available online 16 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Hydrogen Energy〈/p〉 〈p〉Author(s): Xin Zheng, Kaili Xu, Qingsheng Wang, Ruiqing Shen, Yantong Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wet dust removal systems pose hydrogen fire and explosion risks because accumulated aluminium dust can react with water to produce hydrogen gas. Traditionally, hydrogen sensors, alarm devices, explosion-proof electrical components and pressure relief devices are installed in wet dust removal systems to mitigate such risks. However, these safety strategies cannot fundamentally prevent the occurrence of hydrogen fires and explosions. In this work, calcium lignosulfonate (CLS), which is an abundant, inexpensive and renewable chemical, is used to inhibit hydrogen production. Through a series of hydrogen inhibition experiments using CLS solution, a hydrogen inhibition method is proposed. The hydrogen evolution curves of aluminium particles after reaction with CLS solutions at different concentrations reveal that when the concentration of the CLS solution reaches 0.5 g/L, essentially no hydrogen gas is produced. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) are used to characterize the aluminium particles before and after reaction. The film formation behaviour of CLS on the surface of aluminium particles is characterized. The results show that CLS is a good inhibitor and that the adsorption of CLS on the aluminium particle surface obeys the Langmuir adsorption isotherm. Additionally, Fourier transform infrared (FT-IR) analysis is conducted to reveal the physicochemical mechanism of hydrogen inhibition. The application of CLS solution in wet aluminium dust removal systems results in the maximum reduction in hydrogen explosion risk.〈/p〉〈/div〉 〈/div〉