ALBERT

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science〈/p〉 〈p〉Author(s): J. Mohanraj, D. Durgalakshmi, R. Ajay Rakkesh, S. Balakumar, Saravanan Rajendran, Hassan Karimi-Maleh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The demand for high-quality graphene for electronic applications is increasing due to its high carrier mobility and electrical conductivity. In this connection, printing technology is a reliable method towards the fabrication of conductive, disposable graphene-based electrode for low-cost sensor application. Herein we aimed to report the synthesis of high-quality graphene nanosheets obtained by electrochemical exfoliation of biomass-derived from corn cob. The conductive ink was prepared from this exfoliated graphene and was utilized for the preparation of paper-based graphene electrode towards double stranded DNA (dsDNA) sensor application. This paper, based graphene electrode opens the possibility of direct electrochemical analysis of analyte without any sample preparation. In this study, two irreversible oxide peaks were obtained from paper-based printed graphene electrode, corresponds to oxidation of guanine (G) and adenine (A) of dsDNA in the linear range of 0.2 pg mL〈sup〉-1〈/sup〉 to 5 pg mL〈sup〉-1〈/sup〉 with the detection limit of 0.68 pg mL〈sup〉-1〈/sup〉 and the sensitivity of 0.00656 mA pg〈sup〉-1〈/sup〉 cm〈sup〉-2〈/sup〉. Further, a small-scale printable circuit is fabricated using this graphene shows good conductivity of 1.145x10〈sup〉3〈/sup〉(S/m).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720301041-ga1.jpg" width="252" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science〈/p〉 〈p〉Author(s): N.V. Srikanth Vallabani, Ajayan Vinu, Sanjay Singh, Ajay Karakoti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An alarming increase in bacterial resistance towards various types of antibiotics makes it imperative to design alternate or combinational therapies to treat stubborn bacterial infections. In this perspective, emerging tools like nanozymes, nanomaterials with biological enzyme like characteristics, are being utilised to control infections caused by bacterial pathogens. Among several nanozymes used for antibacterial applications, Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles (NP) received great attention due to their effective peroxidase like activity. The pH dependent peroxidase activity of Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 NP results in generation of 〈strong〉〈sup〉.〈/sup〉〈/strong〉OH radical via the unique Fenton chemistry of iron. However, their pH dependent activity is restricted to acidic environment and dramatic loss in antibacterial activity is observed at near neutral pH. Here we describe a novel strategy to overcome the pH lacunae of citrate coated Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 NP by utilizing adenosine triphosphate disodium salt (ATP) as a synergistic agent to accelerate the 〈strong〉〈sup〉.〈/sup〉〈/strong〉OH radical production and restore its antibacterial activity over a wide range of pH. This synergistic combination (30 µg/mL Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 NP and 2.5 mM ATP) shows a high bactericidal activity against both gram positive (〈em〉B. subtilis〈/em〉) and gram negative (〈em〉E. coli〈/em〉) bacterial strains, in presence of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉, at neutral pH. The synergistic effect (Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 NP + ATP) is determined from the viability assessment and membrane damage studies and is further confirmed by comparing the concentration of generated 〈strong〉〈sup〉.〈/sup〉〈/strong〉OH radicals. Over all, this study illustrates ATP assisted and 〈strong〉〈sup〉.〈/sup〉〈/strong〉OH-mediated bactericidal activity of Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanozyme at near neutral pH.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Schematic illustrating the antibacterial activity of Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanozyme via hydroxyl radical generation at near neutral pH〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720301132-ga1.jpg" width="249" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science〈/p〉 〈p〉Author(s): Haixin Zhao, Shu Cui, Guodong Li, Nan Li, Xiaotian Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, photocatalysts with a hollow mesoporous structure have drawn increasing interest owing to their extensive application in environmental protection. Herein, we prepared hollow mesoporous TiO〈sub〉2〈/sub〉 nanospheres decorated with few layer 1T- and 2H- mixed phase MoS〈sub〉2〈/sub〉 nanosheets via a template-based method and a hydrothermal reaction. The as-synthesized samples are of hollow mesoporous structure and high specific surface area, providing abundant mass transport and active sites for photocatalytic reaction. 1T-MoS〈sub〉2〈/sub〉 in the mixed phase MoS〈sub〉2〈/sub〉 mainly play the role as a bridge that transfers photoexcited electrons. Besides, the heterojunction between MoS〈sub〉2〈/sub〉 and TiO〈sub〉2〈/sub〉 can also efficiently restrain the recombination of photogenerated charge carriers in photocatalysts. As a consequence, under UV–vis light irradiation, the hollow porous TiO〈sub〉2〈/sub〉/MoS〈sub〉2〈/sub〉 presents a remarkable photocatalytic activity in rhodaming B degradation. Scavenger studies demonstrate that the primary active species in photocatalytic process are hydroxyl radicals. Moreover, a possible photocatalytic reaction mechanism has also been put forward.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720301144-ga1.jpg" width="451" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science〈/p〉 〈p〉Author(s): Yunyu Cai, Yajun Zhang, Sihan Ji, Yixing Ye, Shouliang Wu, Jun Liu, Shaopeng Chen, Changhao Liang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For the potential use of Au nanoparticles (NPs) in photothermal therapy, it is important and effective to achieve the uniaxial assembly of Au NPs to allow enhanced absorption in the near infrared (NIR) region. Herein, we first presented the construction of amorphous selenium encapsulated gold (Se@Au) chain-oligomers by successive laser ablation of Au and Se targets in sodium chloride solution without other toxic precursors, stabilizers, or templating molecules. Se@Au chain-oligomers showed evidently enhanced NIR absorption and excellent photothermal transduction efficiency (η), which was higher than 47% at 808 nm. After being stored for 1 year, the Se@Au colloids still exhibited outstanding photothermal performance. The cytotoxicity assay demonstrated that there is negligible toxicity of Se@Au chain-oligomers in cells, but cell viability declined to only 1% in phototherapeutic experiments that were implemented in vitro. In intracellular Reactive Oxygen Species (ROS) generation measurements, Se@Au chain-oligomers could trigger a 35.9% increment of ROS upon laser irradiation. The possible synergetic effects between the anticancer function of Se and photothermal behaviors of Se@Au oligomers were intended to increase ROS level in cells. Therefore, such designed Se@Au chain-oligomers of high stability exhibit promising potential for their use as in vivo photothermal therapeutic agents.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720301120-ga1.jpg" width="377" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science〈/p〉 〈p〉Author(s): Sen Liu, Yaqing Zhang, Shang Gao, Teng Fei, Yong Zhang, Xuejun Zheng, Tong Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Here, we report an organometallic chemistry-assisted method for modification of zinc oxide (ZnO) nanoparticles by tin oxide (SnO〈sub〉2〈/sub〉) nanoparticles, providing a novel and efficient approach for preparation of metal oxides-based heterojunction. The SnO〈sub〉2〈/sub〉/ZnO heterojunctions were prepared by modification of ZnO nanoparticles with (CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉SnCl〈sub〉2〈/sub〉 through organometallic chemistry reaction firstly, and subsequently thermal treatment in air atmosphere. The combined characterizations indicate the successful formation of ZnO/SnO〈sub〉2〈/sub〉 heterojunctions with controllable surface oxygen vacancy concentrations by optimizing organometallic chemistry reactions. Most importantly, ZnO-Sn-0.75-based NO〈sub〉2〈/sub〉 sensor delivers the response of 14.3 toward 0.5 ppm NO〈sub〉2〈/sub〉 at 190 °C with response time of 100 s and recovery time of 101 s. It is also found that ZnO-Sn-0.75 sample exhibits better NO〈sub〉2〈/sub〉 sensing performances than ZnO nanoparticles and other ZnO-Sn samples (ZnO-Sn-0.50, and ZnO-Sn-1.0). The excellent sensing performances of ZnO-Sn-0.75 are attributed to the synergistic effect n-n heterojunction and controllable surface oxygen species. The present work opens a generalized avenue for facile, cheap and mass production of transition metal oxides-based heterojunctions for various applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S002197972030103X-ga1.jpg" width="478" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 566〈/p〉 〈p〉Author(s): Lopamudra Acharya, Susanginee Nayak, Sambhu Prasad Pattnaik, Rashmi Acharya, Kulamani Parida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Antibiotic contaminants have received much attention due to the increasing serious environmental concerns. In this work, for the first time, we have fabricated a series of significant type-II p-n heterostructure with Z-scheme charge transfer between p-type B-doped g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 with different proportion of 〈em〉n〈/em〉-type BN through a simple in-situ growth process. PXRD, FTIR, UV–Vis, FESEM, HRTEM and EIS analysis were applied for the detailed characterization of the as-prepared composites to study the crystal phase, structural features, optical and electrical properties. The photocatalytic behaviour of BN/BCN photocatalyst was investigated by the degradation of tetracycline hydrochloride under solar light illumination. Experimental results revealed that about 88.1% of TCH was degraded by the BN/BCN composite containing 4 wt% BN in the BN/BCN matrix, in 60 min of solar light irradiation. Reduction in recombination rate of photo generated electron-hole pair’s and enhanced visible light absorption ability is credited to the enhanced photocatalytic performance of BN/BCN composite. Trapping experiment for the scavenging agents has confirmed that superoxide (〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉O〈sub〉2〈/sub〉¯) and hydroxyl (OH〈sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉〈/sup〉) radicals are the main reactive species during the TCH degradation process. The high stability shown by the BN/BCN composite opens a new path for designing of significant BN based Z-scheme photocatalyst for prevention of environmental issues.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The current study involves BN modified BCN nanocomposite for the effective photocatalytic degradation of TCH under solar light irradiation. This investigation emphasises on type-II p-n heterojunction with solid-state Z-scheme charge transfer pathway for the enhanced photocatalytic performance of BN/BCN heterostructure towards TCH degradation.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720300886-ga1.jpg" width="422" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 566〈/p〉 〈p〉Author(s): Maoz Dor, Yael Levi-Kalisman, Ruarri J. Day-Stirrat, Yael Mishael, Simon Emmanuel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Clay mineral properties, together with solution chemistry, control the assembly of clay platelets into hierarchical structures, including tactoids and aggregates. We studied the effect of salinity on the assembly of kaolinite, illite, and montmorillonite at three critical scales: platelet, tactoid, and aggregate, using cryogenic scanning electron microscopy (cryo-SEM), atomic force microscopy (AFM) and cryo-transmission EM (cryo-TEM), respectively. Cyro-SEM images coupled with original alignment analysis indicate that the degree of aggregate alignment in an ionized solution was significantly higher than in deionized water. Furthermore, upon increasing platelet-platelet bonding energy (montmorillonite 〉 illite 〉 kaolinite), tactoid size increased, packing was less ordered, and aggregate alignment decreased. AFM measurements showed that an increase in ionic-strength caused a decrease in the Young’s modulus of the clays, indicating higher tactoid alignment, since, disordered structures, comprising various platelet orientations, are stiffer than highly-aligned structures. We successfully measured distances 〈1 nm, for both kaolinite and montmorillonite by cryo-TEM, directly demonstrating that increasing ionic-strength reduces platelet-platelet distances. The outcome of this study offers a new approach and methodology to study fundamental colloid-assembly which will trigger future studies investigating additional parameters affecting assembly such as, temperature, solution pH, natural organic matter, and anthropogenic activity.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720301004-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 566〈/p〉 〈p〉Author(s): Ming Wu, Jing Xie, Anjie Liu, Wei Jia, Yali Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Core-shell Fe〈sub〉3〈/sub〉C@N〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉C nanostructures constructed by Fe〈sub〉3〈/sub〉C core encapsulated in N-doped carbon nanotubes (FFCN-MP4000) is designed and readily prepared via a facile and economical solid-state chemical route. By controlling the proportion of C and N in the starting materials, the composition of Fe〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉N〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉C core-shell nanotubes was optimized, then provided more possible active sites as electrocatalysts, exhibited superior oxygen reduction performance. Onset potential (E〈sub〉onset〈/sub〉) of 0.96 V versus reversible hydrogen electrode (RHE) and half-wave potential (E〈sub〉1/2〈/sub〉) of 0.83 V vs RHE was obtained in 0.1 M KOH, which are comparable to those of the commercial Pt/C catalyst (E〈sub〉onset〈/sub〉 = 0.98 V, E〈sub〉1/2〈/sub〉 = 0.84 V vs RHE). Notably, the limited current density for FFCN-MP4000 can reach to 6.6 mA cm〈sup〉−2〈/sup〉, and it efficiently catalyzes 4-electron reduction of oxygen (n = 3.98) with a hydrogen peroxide yield of below 2.2%. In addition, the methanol tolerance and durability are even superior to commercial Pt/C catalyst. This work provides a facile and economical strategy for the feasible design of oxygen reduction reaction (ORR) electrocatalyst with high activity and low cost in alternative commercial Pt/C electrocatalyst.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A facile, low-cost and solution-free synthesis was utilized to achieve Fe-N-C core-shell nanostructures, which exhibited excellent ORR performance in alkaline medium.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979720300916-ga1.jpg" width="390" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉