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Gaskets and seals are essential components in the operation of proton exchange membrane (PEM) fuel cells and are required for keeping hydrogen and air/oxygen within their individual compartments. The durability of these gaskets and seals is necessary, as it influences not only the lifespan but also the electrochemical efficiency of the PEM fuel cell. In this study, the cause of silicon leaching from silicone gaskets under simulated fuel cell conditions was investigated. Additionally, to reduce silicon leaching, the silica surface was treated with methyltrimethoxysilane, vinyltriethoxysilane, and (3,3,3-trifluoropropyl)trimethoxysilane. Changes in the silica surface chemistry were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, elemental analysis, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Inductively coupled plasma-optical emission spectroscopy analysis revealed that surface-treated silica was highly effective in reducing silicon leaching. [ABSTRACT FROM AUTHOR]

The synthesis of hierarchically porous materials from industrial solid waste as catalysts or adsorbents has attracted much attention in environmental pollution control. The present work highlights the synthesis of a series of MgFeAl layered double hydroxide (LDH) with different ratios of Mg/(Fe + Al) from red mud and ferronickel slag under different pH to decolorize three red dye solutions, namely, Congo red (CR), acid red (AR), and reactive red (RR). The maximum adsorption capacity (386.1 mg.g−1) for CR was obtained by the MgFeAl-LDH sample with Mg/(Fe + Al) mole ratio of 2 synthesized under pH 10. The optimized synthesis parameters led to a high surface area and large pore volume of MgFeAl-LDH, thereby enhancing the mass transfer of adsorbate to the active sites of the adsorbent. Further, the MgFeAl-LDH sample was also efficient in removing AR (120.9 mg.g−1) and RR (114 mg.g−1). Moreover, the adsorption kinetics and isotherms of MgFeAl-LDH fitted well with the pseudo-second-order and Langmuir models, respectively. The MgFeAl-LDH system developed a valuable approach to utilize industrial waste for dye removal. [ABSTRACT FROM AUTHOR]

Water electrolysis is a promising method for producing ultra‐pure hydrogen as a sustainable energy source in the future. In this study, the use of a hollow‐structured Fe‐doped CoP with an abundance of phosphorus defects for both oxygen and hydrogen evolution reactions (OER and HER) is suggested. The as‐prepared electrocatalyst has a low overpotential of 300 and 143 mV to achieve a current density of 10 mA cm−2 for the OER and HER, respectively. When the synthesized electrocatalyst is used as both anode and cathode in a water electrolyzer, the full cell requires a very small cell voltage of 1.63 V at 10 mA cm−2 and exhibits excellent stability for over 100 h. The excellent performance is due to the generation of numerous electrocatalytic active sites induced by introduction of structural defects such as Fe dopants and P vacancies, which modify the adsorption energy of reaction intermediates during water electrolysis. This study can offer new insights into the development of efficient precious metal‐free electrocatalysts for production of renewable energy sources. [ABSTRACT FROM AUTHOR]

Polymethylsilsesquioxane (PMSQ) aerogels have been developed for diverse applications owing to their excellent flexibility and hydrophobicity. PMSQ aerogels, however, are limited by their flammability and low thermal stability. In this study, transparent and robust PMSQ aerogels were synthesized using an environmentally friendly flame retardant, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-vinyltrimethoxysilane (DOPO) in a facile one-pot manner and successfully dried under ambient pressure without cracks. Briefly, methyltrimethoxysilane (MTMS) and another synthesized precursor, DOPO-vinyltrimethoxysilane (DOPO-VTMS), where DOPO and VTMS were covalently bonded, were used to prepare a DOPO-VTMS MTMS aerogel via co-hydrolytic condensation. The DOPO-VTMS MTMS aerogel showed excellent flame retardancy with a peak heat release rate of 23.48 W g−1, which is 60% lower than that of the MTMS aerogel. It also exhibited enhanced thermal stability, as confirmed by thermogravimetric analysis, originating from the synergistic effect of P and Si. Furthermore, the compressive strength of the DOPO-VTMS MTMS aerogel was 26 times higher than that of the MTMS aerogel. With superior thermal properties and mechanical robustness, the preparation strategy employed in this study can contribute to the development of PMSQ aerogels for various applications such as thermal insulation for buildings, flame-retardant airspace dust collectors, or fire preventive coatings for fabrics. [ABSTRACT FROM AUTHOR]

Fluorosilicone rubber (F-LSR) is a promising material that can be applied in various cutting-edge industries. However, the slightly lower thermal resistance of F-LSR compared with that of conventional PDMS is difficult to overcome by applying nonreactive conventional fillers that readily agglomerate owing to their incompatible structure. Polyhedral oligomeric silsesquioxane with vinyl groups (POSS-V) is a suitable material that may satisfy this requirement. Herein, F-LSR-POSS was prepared using POSS-V as a chemical crosslinking agent chemically bonded with F-LSR through hydrosilylation. All F-LSR-POSSs were successfully prepared and most of the POSS-Vs were uniformly dispersed in the F-LSR-POSSs, as confirmed by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) measurements. The mechanical strength and crosslinking density of the F-LSR-POSSs were determined using a universal testing machine (UTM) and dynamic mechanical analysis (DMA), respectively. Finally, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements confirmed that the low-temperature thermal properties were maintained, and the heat resistance was significantly improved compared with conventional F-LSR. Eventually, the poor heat resistance of the F-LSR was overcome with three-dimensional high-density crosslinking by introducing POSS-V as a chemical crosslinking agent, thereby expanding the potential fluorosilicone applications. [ABSTRACT FROM AUTHOR]

A novel chiral porous column was fabricated by lipase immobilized MIL-100(Fe) biocomposites as chiral stationary phase through covalent coupling and applied to capillary electrochromatographic enantioseparation. MOF-based lipase biocomposites not only enhance stereoselective activities but also improve the stability and applicability of the enzyme. The functionalized porous columns were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and powder X-ray diffraction. The performance of the porous column was evaluated by enantioseparating amino acid enantiomers, affording high resolution over 2.0. Besides, the enantio-resolutions of phenylephrine, phenylsuccinic acid, chloroquine, and zopiclone were also greater than 2.0. The relative standard deviations of run-to-run, intra-, and inter-day repeatability were within 4.0% in terms of resolution and retention time, exhibiting excellent stability of the column. Conceivably, the results show that MOF-based lipase composites as chiral stationary phase offer a highly efficient means for enantioseparation in capillary electrochromatography, attributing to the enhanced enantioselective activities of lipase by highly ordered frameworks. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuators (DEAs), a type of electroactive polymers (EAPs), are smart materials that are used in various fields such as artificial muscles and biomimetic robots. In this study, graphene nanoplatelets (GNPs), which are conductive carbon fillers, were added to a widely used DEA, namely, polydimethylsiloxane (PDMS), to improve its low actuated strain. Four grades of GNPs were used: H5, H25, M5, and M25 (here, the number following the letter indicates the average particle size of the GNPs in μm). The average layer thickness of the H grade is 13–14 nm and that of the M grade is 5–7 nm. PDMS composites were prepared by adding 0.5, 1, 2, and 3 wt% of each GNP, following which the mechanical properties, dielectric properties, and actuated strain of the composites were measured. The mechanical properties were found to increase as the particle size increased. Regarding the dielectric characteristics, it was found that the higher the aspect ratio of the filler, the easier the formation of a micro-capacitor network in the composite—this led to an increase in the dielectric constant. In addition, the higher amounts of GNPs in the composites also led to an increase in the dielectric constant. For the actuated strain analysis, the electromechanical sensitivity was calculated using the ratio of the dielectric constant to the Young's modulus, which is proportional to the strain. However, it was found that when the loss tangent was high, the performance of the actuated strain decreased owing to the conversion of electric energy into thermal energy and leakage current loss. As a result, the highest actuated strain was exhibited by the M25 composite, with an actuated strain value of 3.01% measured at a low electric field (<4 kV/mm). In conclusion, we proved that the GNP–PDMS composites with a thin layer and large particle size exhibited high deformation. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of a strongly coupled Co3O4/CoS microbox heterostructure, prepared through an annealing treatment with the subsequent hydrothermal sulfidation of a Co–Co Prussian blue analog (PBA) precursor. The unique 3D hierarchical architecture and potential synergies of Co3O4 and CoS provide benefits to the Co3O4/CoS heterostructure for both oxygen reduction and evolution reactions (ORR and OER). It displays comparable ORR catalytic activity (half-wave potential of 0.820 V) to state-of-the-art Pt/C but better durability and methanol tolerance. The Co3O4/CoS electrocatalyst also shows high OER activity with a relatively low overpotential (349 mV at 10 mA cm−2) and small Tafel slope (66.6 mV dec−1), compared to those of commercial RuO2 (366 mV at 10 mA cm−2 and 86.3 mV dec−1, respectively), making it a potential bifunctional electrocatalyst for both the ORR and the OER. Moreover, a rechargeable Zn–air battery with a Co3O4/CoS cathode shows a higher cell voltage (1.51 V), higher power density (168 mW cm−2 at 269 mA cm−2), and better cycling stability (up to 150 cycles) than the same battery with the state-of-the-art Pt/C + RuO2 catalyst. This PBA-based material with a strongly coupled interface between Co3O4 and CoS offers insights into the development of low-cost and highly efficient electrocatalysts for diverse energy-related applications. [ABSTRACT FROM AUTHOR]

Graphite exhibits electromagnetic wave attenuation and high electrical conductivity. In this study, we analyzed the electromagnetic interference shielding effectiveness (EMI SE) performance and electric conductivity of composites fabricated by varying the size (mean size: 6–100 µm) of graphite fillers and explained resulting attributes through the relative permittivity and geometrical characteristics of the filler. When the graphite/paraffine wax composite was fabricated using large-sized graphite (KS150), the spacing between the graphite fillers became widened, enabling electromagnetic waves to leak through the gap. The analysis results indicated that KS150 graphite exhibited an EMI SE performance of under 10 dB when the filler content was 30 wt%. However, when the content was increased to 50 wt%, the EMI SE performance improved sharply to 40 dB. In contrast, when the composite was filled with small-sized graphite (KS6), having a high ratio of surface to volume, the EMI SE performance was greater than that with the largesized graphite at low loading. The results related to the EMI shielding performance of graphite-filled composites revealed that the size of the filler greatly affects the EMI SE. The composite using KS75 showed an EMI SE performance of 53.0 dB and electrical conductivity of 2,000 S/m. [ABSTRACT FROM AUTHOR]

Herein, mesoporous NiFe2O4 spinel nanoparticles with abundant oxygen vacancies are successfully prepared by a simple hydrothermal method followed by mild H2 reduction and used as catalysts for the oxygen evolution reaction. Compared with the pristine and air‐treated NiFe2O4, the H2‐treated NiFe2O4 shows a much lower overpotential of 389 mV at a current density of 10 mA cm−2. The H2‐treated NiFe2O4 also indicates substantial long‐term stability even after 1000 cyclic tests. This outstanding electrochemical activity and stability can be attributed to the improved physicochemical properties by H2 treatment: small nanoparticles with well‐developed mesoporous structures, a high ratio of Ni2+/Ni3+ cations, and abundant oxygen vacancies. These properties can significantly improve charge transfer kinetics and increase the number of active sites on the catalyst. The results demonstrate that this facile fabrication method is a promising route for developing cost‐effective and high‐performance catalysts to be used in electrochemical applications. [ABSTRACT FROM AUTHOR]

Water pollution due to heavy metal ions from factories causes serious threats as the heavy metal ions are inclined to accumulate in living systems threat ening their health. Adsorption is considered one of the most promising wastewater purification techniques for its simple operation and high effectiveness compared with other techniques. Accordingly, a novel cost-effective and environmentally benign porous melamine-vanillin polymer (MVP) was synthesized via Schiff-base formation reaction, which was utilized for the removal of Pb(II) ions. The MVP achieved a high surface area of 745 m2 g-1 with a hierarchically porous structure consisting of 1 nm and 3–50 nm pores. Effects of the contact time and the initial heavy metal concentration on the adsorption of Pb(II) were studied. Due to the copious functional groups and the hierarchical pore size distribution, MVP was found to exhibit a good adsorption performance toward Pb(II) ions. The adsorption process was well-fitted to the Langmuir adsorption isotherm and the pseudo-1st-order kinetic model. [ABSTRACT FROM AUTHOR]

Significant efforts have been made to enhance the poor intrinsic electrocatalytic activity of MnO2 toward the oxygen reduction reaction (ORR) for practical applications in fuel cells and metal–air batteries. However, the main bottleneck problems of the MnO2 catalyst for the ORR include the poor conductivity and the low activity compared to state-of-the-art Pt/C. Here, high power proton particles (14 MeV) were irradiated on MnO2, and numerous oxygen vacancies were introduced into the surface of MnO2 by decomposing water radiolytically along the proton beam. Compared with the pristine MnO2, the proton-treated MnO2 showed a much higher current density of −4.6 mA cm−2 at 0.65 V vs. reversible hydrogen electrode (RHE). The proton-treated MnO2 exhibited excellent catalytic durability, maintaining 95 % of its activity after a 10 000 s chronoamperometric stability test. This outstanding ORR performance and stability can be attributed to the improved physicochemical properties resulting from the proton beam irradiation. This study provides a novel approach for the generation of oxygen vacancies by proton irradiation, improving the catalyst for use as an advanced electrode material. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the kinetics of polymerization and the properties of polyurethane (PU) synthesized from renewable sources named iPU using isosorbide (ISB), cPU using caster oil (CO), and hPU using the both. The synthesis was carried out via two-step polymerization by varying the contents of CO and ISB. The reaction rate, determined by FTIR, of the bio-based monomers was slower than that of the petroleum-based monomers. The activation energy was calculated from the reaction rate under different conditions. The physicochemical, morphological, and mechanical properties were examined by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and universal testing machine (UTM). The weight-average molecular weights (Mw) were in the range of 13,288 to 62,212 g·mol-1, glass transition temperature (Tg) of -30.9 to -33.3 oC, tensile strengths of 1.29 to 14.14 MPa, and elongation at breaks of 28 to 1,358%. [ABSTRACT FROM AUTHOR]

We propose a simple method to investigate both the qualitative and quantitative properties of titanium tetrachloride. The selection and concentration of the employed solvent were found to be very important in the analysis of highly reactive titanium tetrachloride (TiCl4). Herein, we employed various concentrations of an acid solution to serve as a stabilizing medium. Qualitative analysis was performed via Fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Additionally, the quantitative analysis was performed via inductively coupled plasma optical emission spectroscopy (ICP-OES). We concluded that both the qualitative and quantitative properties of titanium tetrachloride could be easily measured using a specific acidic solvent as a medium. [ABSTRACT FROM AUTHOR]

Thermally expandable microspheres were prepared by suspension polymerization using low-temperature initiators. The copolymer shells were made from acrylonitrile (AN) and methyl methacrylate (MMA) as the major monomers. Methacrylonitrile (MAN) was used as the third monomer to improve the expansion performance of the microspheres. This study investigated the influences of the initiator species, polymerization temperature, initiator content, and polymerization pressure on the expansion performance. Stable expandable microcapsules and good thermal characteristics were obtained successfully using 1.5 wt% azobis(4-methoxy-2.4- dimethyl valeronitrile) (V-70) as an initiator at a low temperature of 35 °C and at polymerization pressure of 3 bar. The resulting particle size without destruction and secondary nucleation showed a mean diameter of 30 μm under the optimal conditions. The encapsulated contents of the blowing agent were confirmed by thermogravimetric analysis (TGA) to be 40%. [ABSTRACT FROM AUTHOR]

Porous carbon foams were fabricated using phenol and formaldehyde (PF) as carbon precursors. The pore size and porosity of the foams were controlled using glycol-derivatives as porogen during condensation polymerization. The morphology of the resulting carbon foam with macroporous porosity and well dispersed pore structures were verified by mercury porosimetry and scanning electron microscopy. The compressive stress of the resulting carbon foam increased with increasing molecular weights of glycol-derivatives due to the decrease in porosity. Furthermore, the reaction mechanism was identified to involve glycol-derivatives in the condensation reaction of PF, which generated the porosity of the resulting carbon foam by releasing volatile compounds according to thermogravimetric analysis and Fourier transform infrared spectroscopy. As a result, the mechanical properites of the carbon foam could be affected by the morphological properties of macroporous structures using different types and concentrations of glycol-derivatives. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) were uniformly coated with silica using polyethyleneimine (PEI) as a coupling agent without subjecting the surfaces of the MWCNTs to chemical modification, such as an amine treatment or chemical oxidation. PEI was physically adsorbed onto the MWCNTs, and the silica coating process was performed through a sol-gel reaction of tetraethyl orthosilicate (TEOS) in ethanol under base catalytic conditions at room temperature. PEI was the best coupling agent for coating silica on MWCNTs among the various amphiphilic polymers and surfactant tested, which included Triton X-100, polyvinylpyrrolidone, polyethylene glycol, and sodium dodecyl sulfate. During the sol-gel process using PEI as a coupling agent, silica could be uniformly formed on MWCNTs without any structural defects. As the amount of TEOS used was increased, the thickness of coated silica layer and electrical resistivity of MWCNTs also increased (up to 5.3×10 Ω sq) owing to the high surface coverage of silica on the MWCNTs. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Polyacrylonitrile (PAN) is a favored material for electrospinning and also has been used successfully as a raw material of carbon nanofiber due to its useful and stable structure after treating adequate energy. The PAN nanofibers were prepared and irradiated by electron beam with different dose levels in order to confirm the most efficient dose level on nanofibers. The object of this work is to identify the stabilization of PAN during the irradiation and the effect caused from electron beam irradiation on PAN nanofiber sheets. Upon irradiation, the diameter of nanofibers decreased and the surface area accordingly increased. From structural analyses, that the degree of stabilization increases up to 2000 kGy by disruption C≡N group on PAN. Only short irradiation time less than 1 min can cause the stabilization effect that can be obtained from time-consuming thermal stabilization process. [ABSTRACT FROM AUTHOR]

Manganese dioxide (MnO) was synthesized in the forms of nanorods, nanoparticles, and mesoporous structures and the characteristics of these materials were investigated. Crystallinities were studied by x-ray diffraction and morphologies by scanning and transmission electron microscopy. Average pore sizes and specific surface areas were analyzed using the Barret-Joyner-Halenda and Brunauer-Emmett-Teller methods, respectively. Samples were also studied by cyclic voltammetry using 1M aqueous KOH solution saturated with either O or N as electrolytes to investigate their ORR (oxygen reduction reaction) and OER (oxygen evolution reaction) activities. Of the samples produced, mesoporous MnO exhibited the highest ORR and OER catalytic activities. Mesoporous MnO supported on a gas diffusion layer was also used as a catalyst on the air electrode (cathode) of a lithium-air battery in organic electrolyte. The charge-discharge behavior of mesoporous MnO was investigated at a current density 0.2 mAcm in a pure oxygen environment. Mesoporous MnO electrodes showed stable cycleability up to 65 cycles at a cell capacity of 700 mAhg. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of lactic acid to propylene glycol was performed over various metals (Ag, Co, Cu, Ni, Pt, and Ru) supported on silica prepared by an incipient wetness impregnation method. The loading amount of each metal was 5 wt%. Crystallinity of the synthesized catalysts was investigated by X-ray diffraction (XRD), and the BET method was utilized to examine the surface area. Pore volume and pore size of catalysts were determined using BJH analysis of the N adsorption isotherm. Particle sizes of various metals were determined from transmission electron microscopy (TEM) images. The catalytic activity was found to be strongly dependent on the supported metal. Among catalysts tested, Ru/SiO showed the highest propylene glycol yield. The yield of propylene glycol increased with pressure, and the highest yield was achieved at 130 °C. [ABSTRACT FROM AUTHOR]

Carbon aerogels were prepared by polycondensation of resorcinol with formaldehyde in ambient conditions. The effect of resorcinol-to-catalyst ratio (R/C ratio) on volume shrinkage, BET surface area, and electrochemical property was investigated by changing R/C ratio from 50 to 2000. Carbon aerogel prepared at R/C ratio of 500 showed less than 2% of volume shrinkage and the highest BET surface area (706 m/g). Specific capacitance of carbon aerogel prepared at R/C ratio of 500 was found to be 81 F/g in 1M HSO electrolyte. Cobalt-doped carbon aerogels were then prepared by an impregnation method with a variation of cobalt content, and their performance was investigated. Among the samples prepared, 7 wt% cobalt-doped carbon aerogel showed the highest capacitance (100 F/g) and the most stable cyclability. The enhanced capacitance of cobalt-doped carbon aerogel was attributed to the faradaic redox reactions of cobalt oxide. [ABSTRACT FROM AUTHOR]

The influence of electron beam irradiation on the electrochemical properties of electrodeposited V2O5 thin films was investigated. V2O5 thin films were deposited electrochemically onto indium tin oxide-coated glass from an aqueous vanadyl sulfate hydrate (VOSO4⋅ nH2O) solution using Pt and Ag/AgCl as the counter electrode and reference electrode, respectively. Electrodeposition was performed potentiostatically at 1.7 V vs. Ag/AgCl. Electrodeposited samples were then subjected to a 1-MeV electron beam using an electron beam accelerator at the Korea Atomic Energy Research Institute. For comparison, a control sample was not irradiated with the electron beam. Crystallinity change before and after electron beam irradiation was investigated by X-ray diffraction and the oxidation state of vanadium determined by X-ray photoelectron spectroscopy. Scanning electron microscopy was utilized to examine surface morphology. It was observed that electron beam irradiation altered the oxidation state of vanadium and increased crystallinity. Significant morphological changes of V2O5 thin films were also observed with electron beam irradiation. Cyclic voltammetry was employed to evaluate the electrochemical properties of the synthesized V2O5 films in terms of their application as electrodes of lithium-ion battery. Compared with the control sample, which was not irradiated with an electron beam, the electron beam-irradiated V2O5 specimens showed much higher capacitance. [ABSTRACT FROM AUTHOR]

MoO/Pt binary catalysts with various Mo/Pt ratios were prepared by an electrodeposition method for use as the anode in a direct methanol fuel cell. Pt was electrodeposited onto indium tin oxide (ITO) substrate, and then MoO was electrodeposited from an Mo-peroxo electrolyte on the top of Pt with different deposition times. The crystallinity of synthesized films was analyzed by X-ray diffraction (XRD), and the oxidation state of both the platinum and molybdenum were determined by X-ray photoelectron spectroscopy (XPS) analyses. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM/EDS) was employed to investigate the surface morphology and composition. The catalytic activity and stability for methanol oxidation were measured using cyclic voltammetry and chronoamperometry in a mixture of 0.5 M HSO and 0.5 M CHOH aqueous solution. Electrocatalytic activity for CO oxidation was also evaluated in a 0.5-M HSO solution. The addition of a proper amount of MoO was found to significantly improve both the catalytic activity and stability for methanol oxidation. [ABSTRACT FROM AUTHOR]

Acidity of polyatom-substituted H nPW11M1O40 (M=V, Nb, Ta, and W) Keggin heteropolyacids (HPAs) was measured by NH3-TPD experiments. Acidity decreased in the order of H3PW11W1O40>H4PW11V1O40>H4PW11Nb1O40>H4PW11Ta1O40. Vapor-phase dehydration of cyclohexanol was conducted as a model reaction to correlate the acidity with the acid catalysis of HPA catalysts. Yield for cyclohexene (a product by acid catalysis) increased with increasing acidity of H nPW11M1O40 (M=V, Nb, Ta, and W) HPA catalysts. The acidity of H nPW11M1O40 (M=V, Nb, Ta, and W) HPA catalysts could be utilized as a probe of acid catalysis for dehydration of cyclohexanol. [ABSTRACT FROM AUTHOR]

Au supported on metal oxides (P-25, HPA) was successfully synthesized by PS-PVP block copolymer encapsulation method. The size of nanoparticles was strongly dependent on calcination conditions (time and temperature). The particle size was also controlled by selection of the appropriate length of PVP part in block copolymer. When particulate gold was doped on the surface of P-25, it strongly improved visible light absorption by plasma resonance. Compared with pure TiO, Au supported on P-25 demonstrated much higher photocatalytic activity for acetaldehyde decomposition under visible light illumination. The enhanced photocatalytic activity could be attributed to the increase of visible light absorption and catalytic activity of nanoparticulate Au. [ABSTRACT FROM AUTHOR]

An automated system for high-throughput electrochemical synthesis and screening of fuel cell electro-oxidation catalysts is described. This system consists of an electrode probe that contains counter and reference electrodes that can be positioned inside an array of electrochemical cells created within a polypropylene block. The electrode probe is attached to an automated of X-Y-Z motion system. An externally controlled potentiostat is used to apply the electrochemical potential to the catalyst substrate. The motion and electrochemical control are integrated using a user-friendly software interface. During automated synthesis the deposition potential and/or current may be controlled by a pulse program triggered by the software using a data acquisition board. The screening includes automated experiments to obtain cyclic voltammograms. As an example, a platinum-tungsten oxide (Pt-WO3) library was synthesized and characterized for reactivity towards methanol electro-oxidation. [ABSTRACT FROM AUTHOR]

The reactivity of gold clusters (8–22 nm diameter) supported on different metal oxides (titanium dioxide (TiO2), zinc oxide (ZnO), zirconium oxide (ZrO2), and silicon dioxide (SiO2)) was investigated in a continuous flow reactor. Clusters were encapsulated within polymer in toluene solution, impregnated onto the bulk supports, and reduced by calcination at 300 °C. Support dependent sintering (TiO2>ZrO2>ZnO) was observed following heating in air at 300 °C. For both CO oxidation and propylene hydrogenation, Au nanoclusters on TiO2 exhibit the highest activity compared to other supports. [ABSTRACT FROM AUTHOR]

Keywords: spinel-type oxide; oxygen vacancy; electrocatalyst; oxygen evolution reaction; water splitting The oxygen-deficient spinel-type oxide nanoparticles exhibited excellent electrocatalytic activity and long-term durability for the OER in alkaline medium. Spinel-type oxide, oxygen vacancy, electrocatalyst, oxygen evolution reaction, water splitting. [Extracted from the article]