ALBERT

Description: Metal organic frameworks (MOFs) built from a single small ligand typically have high stability, are rigid, and have syntheses that are often simple and easily scalable. However, they are normally ultra-microporous and do not have large surface areas amenable to gas separation applications. We report an ultra-microporous (3.5 and 4.8 Å pores) Ni-(4-pyridylcarboxylate) 2 with a cubic framework that exhibits exceptionally high CO 2 /H 2 selectivities (285 for 20:80 and 230 for 40:60 mixtures at 10 bar, 40°C) and working capacities (3.95 mmol/g), making it suitable for hydrogen purification under typical precombustion CO 2 capture conditions (1- to 10-bar pressure swing). It exhibits facile CO 2 adsorption-desorption cycling and has CO 2 self-diffusivities of ~3 x 10 –9 m 2 /s, which is two orders higher than that of zeolite 13X and comparable to other top-performing MOFs for this application. Simulations reveal a high density of binding sites that allow for favorable CO 2 -CO 2 interactions and large cooperative binding energies. Ultra-micropores generated by a small ligand ensures hydrolytic, hydrostatic stabilities, shelf life, and stability toward humid gas streams.

Description: 〈p〉Electrocatalytic transformation of carbon dioxide (CO〈sub〉2〈/sub〉) and water into chemical feedstocks offers the potential to reduce carbon emissions by shifting the chemical industry away from fossil fuel dependence. We provide a technoeconomic and carbon emission analysis of possible products, offering targets that would need to be met for economically compelling industrial implementation to be achieved. We also provide a comparison of the projected costs and CO〈sub〉2〈/sub〉 emissions across electrocatalytic, biocatalytic, and fossil fuel–derived production of chemical feedstocks. We find that for electrosynthesis to become competitive with fossil fuel–derived feedstocks, electrical-to-chemical conversion efficiencies need to reach at least 60%, and renewable electricity prices need to fall below 4 cents per kilowatt-hour. We discuss the possibility of combining electro- and biocatalytic processes, using sequential upgrading of CO〈sub〉2〈/sub〉 as a representative case. We describe the technical challenges and economic barriers to marketable electrosynthesized chemicals.〈/p〉

Description: Earth-abundant first-row (3d) transition metal-based catalysts have been developed for the oxygen-evolution reaction (OER); however, they operate at overpotentials substantially above thermodynamic requirements. Density functional theory suggested that non-3d high-valency metals such as tungsten can modulate 3d metal oxides, providing near-optimal adsorption energies for OER intermediates. We developed a room-temperature synthesis to produce gelled oxyhydroxides materials with an atomically homogeneous metal distribution. These gelled FeCoW oxyhydroxides exhibit the lowest overpotential (191 millivolts) reported at 10 milliamperes per square centimeter in alkaline electrolyte. The catalyst shows no evidence of degradation after more than 500 hours of operation. X-ray absorption and computational studies reveal a synergistic interplay between tungsten, iron, and cobalt in producing a favorable local coordination environment and electronic structure that enhance the energetics for OER.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Zhang, Bo -- Zheng, Xueli -- Voznyy, Oleksandr -- Comin, Riccardo -- Bajdich, Michal -- Garcia-Melchor, Max -- Han, Lili -- Xu, Jixian -- Liu, Min -- Zheng, Lirong -- Garcia de Arquer, F Pelayo -- Dinh, Cao Thang -- Fan, Fengjia -- Yuan, Mingjian -- Yassitepe, Emre -- Chen, Ning -- Regier, Tom -- Liu, Pengfei -- Li, Yuhang -- De Luna, Phil -- Janmohamed, Alyf -- Xin, Huolin L -- Yang, Huagui -- Vojvodic, Aleksandra -- Sargent, Edward H -- New York, N.Y. -- Science. 2016 Apr 15;352(6283):333-7. doi: 10.1126/science.aaf1525. Epub 2016 Mar 24.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. Department of Physics, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China. ; Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China. ; Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. ; SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA. SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ; Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA. ; Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. ; Canadian Light Source (CLS), 44 Innovation Boulevard, Saskatoon, SK, S7N 2V3, Canada. ; Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China. ; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA. ; SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA. SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ted.sargent@utoronto.ca alevoj@stanford.edu. ; Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. ted.sargent@utoronto.ca alevoj@stanford.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27013427" target="_blank"〉PubMed〈/a〉

Description: Selective electrocatalysts are urgently needed for carbon dioxide (CO 2 ) reduction to replace fossil fuels with renewable fuels, thereby closing the carbon cycle. To date, noble metals have achieved the best performance in energy yield and faradaic efficiency and have recently reached impressive electrical-to-chemical power conversion efficiencies. However, the scarcity of precious metals makes the search for scalable, metal-free, CO 2 reduction reaction (CO 2 RR) catalysts all the more important. We report an all-organic, that is, metal-free, electrocatalyst that achieves impressive performance comparable to that of best-in-class Ag electrocatalysts. We hypothesized that polydopamine—a conjugated polymer whose structure incorporates hydrogen-bonded motifs found in enzymes—could offer the combination of efficient electrical conduction, together with rendered active catalytic sites, and potentially thereby enable CO 2 RR. Only by developing a vapor-phase polymerization of polydopamine were we able to combine the needed excellent conductivity with thin film–based processing. We achieve catalytic performance with geometric current densities of 18 mA cm –2 at 0.21 V overpotential (–0.86 V versus normal hydrogen electrode) for the electrosynthesis of C 1 species (carbon monoxide and formate) with continuous 16-hour operation at 〉80% faradaic efficiency. Our catalyst exhibits lower overpotentials than state-of-the-art formate-selective metal electrocatalysts (for example, 0.5 V for Ag at 18 mA cm –1 ). The results confirm the value of exploiting hydrogen-bonded sequences as effective catalytic centers for renewable and cost-efficient industrial CO 2 RR applications.

Description: Carbon dioxide (CO 2 ) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO 2 to ethylene with 70% faradaic efficiency at a potential of –0.55 volts versus a reversible hydrogen electrode (RHE). Hydroxide ions on or near the copper surface lower the CO 2 reduction and carbon monoxide (CO)–CO coupling activation energy barriers; as a result, onset of ethylene evolution at –0.165 volts versus an RHE in 10 molar potassium hydroxide occurs almost simultaneously with CO production. Operational stability was enhanced via the introduction of a polymer-based gas diffusion layer that sandwiches the reaction interface between separate hydrophobic and conductive supports, providing constant ethylene selectivity for an initial 150 operating hours.

Description: In recent times, atomically thin alloys of boron, nitrogen, and carbon have generated significant excitement as a composition-tunable two-dimensional (2D) material that demonstrates rich physics as well as application potentials. The possibility of tunably incorporating oxygen, a group VI element, into the honeycomb sp 2 -type 2D-BNC lattice is an intriguing idea from both fundamental and applied perspectives. We present the first report on an atomically thin quaternary alloy of boron, nitrogen, carbon, and oxygen (2D-BNCO). Our experiments suggest, and density functional theory (DFT) calculations corroborate, stable configurations of a honeycomb 2D-BNCO lattice. We observe micrometer-scale 2D-BNCO domains within a graphene-rich 2D-BNC matrix, and are able to control the area coverage and relative composition of these domains by varying the oxygen content in the growth setup. Macroscopic samples comprising 2D-BNCO domains in a graphene-rich 2D-BNC matrix show graphene-like gate-modulated electronic transport with mobility exceeding 500 cm 2 V –1 s –1 , and Arrhenius-like activated temperature dependence. Spin-polarized DFT calculations for nanoscale 2D-BNCO patches predict magnetic ground states originating from the B atoms closest to the O atoms and sizable (0.6 eV 〈 E g 〈 0.8 eV) band gaps in their density of states. These results suggest that 2D-BNCO with novel electronic and magnetic properties have great potential for nanoelectronics and spintronic applications in an atomically thin platform.