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Transition metal dichalcogenides have been the most attractive two-dimensional layered materials for electrocatalytic hydrogen evolution due to their unique structure and multi-phase electronic states. However, the enhancement of the WSe2 electrocatalytic hydrogen evolution reaction (HER) performance by bimetal co-doping has been rarely reported. Herein, the NiMo–WSe2 catalyst has been synthesized by a one-step hydrothermal reaction, with lower overpotentials of 177 and 188 mV at a current density of 10 mA cm−2 in 0.5 M H2SO4 and 1 M KOH, respectively. The large specific surface area and thinner edge morphology provide more active sites for hydrogen production, thereby significantly improving the charge transfer kinetics. Density functional theory calculation results show that under acidic conditions the ΔGH* values of NiMo–WSe2 with different structures and hydrogen adsorption sites are also different, when the hydrogen adsorption site was located at the top of the Se–Ni bond, the meta NiMo–WSe2 has a ΔGH* value (−0.04 eV) that is closest to 0. Meanwhile, NiMo–WSe2 (meta) also has a minimum of ΔGH* under alkaline conditions. DOS confirmed that Ni doping has a large impact on the electronic states at the WSe2 Fermi level, while NiMo co-doping greatly reduces the potential energy barrier of the HER reaction, jointly increasing the current density, and thus improving the HER performance. [ABSTRACT FROM AUTHOR]

Multi‐size Bi2O3 nanoparticles supported by 1‐dimensional (1D) porous carbon microtubes (ms‐Bi2O3/CMTs) were favorably constructed through surface‐ion release and in‐ situ oxidation strategy. The prominent 1D porous microtube materials with multi‐size nanoparticles structure can furnish more plentiful electrochemical active sites and shorten lithium storage paths for high‐speed redox reactions, which was conducive to ion transport kinetics. The CV tests with various scan rates verified lithium storage mechanism of ms‐Bi2O3/CMTs with diffusion/capacitance control coexistence. The complexes illustrated an ultra‐long cycle life and extraordinary reversible capacity: it still had a specific capacity of 392.6 mAh g−1 after 3000 cycles at 1 A g−1; and it manifested 546.3 mAh g−1 when it returned to 0.05 A g−1 and continued to 100 cycles after experiencing different current densities of 0.05–5 A g−1, which indicated that ms‐Bi2O3/CMTs is a prospective anode for lithium‐ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

Abstract: CH4 pyrolysis and CH4-CO2 reforming to produce syngas was carried out in a quartz tubular reactor over blank and carbonaceous catalyst. Material balance analysis of C atom was conducted according to the calculatedH. The gas composition was detected by an on line gas chromatograph with FPD and PID detector. It was found that CH4 pyrolysis decomposed into carbon and H2. For CH4-CO2 reforming, firstly CH4 decomposed into carbon and H2, the carbon then reacts with carbon monoxide to form carbon dioxide. As a comparison, blank tests were also performed. The results showed that the carbonaceous catalyst greatly decreased the initial reaction temperature (about decreased 50°C), and promoted CH4 conversion. From the material balance analysis of C atom, it can be found that the mass of carbonaceous catalyst reduce during the carbon dioxide reforming reaction of methane. It indicated that the gasification of carbonaceous materials by CO2 takes place during the synthesis process. The consumption kinetics parameters of carbonaceous materials were determined by an overall unreacted shrinking core model. The apparent activation energy of consumption carbonaceous materials was more than 230kJ/mol during CH4-CO2 reforming. [Copyright &y& Elsevier]

Abstract: CO2 reforming of CH4 was studied over laboratory-prepared carbonaceous catalysts at atmospheric pressure (0.1MPa) and high pressure (3.6MPa). The catalysts were characterized by BET and FITR techniques. The catalytic activity and stability of catalysts were closely related to the reaction pressure. It was observed that the use of higher pressure substantially decreased CO2 and CH4 conversion and increased catalyst deactivation during CO2 reforming of CH4, compared to runs at 0.5MPa for carbonaceous catalysts. Deactivation was related to carbon formation. Some process adjustment methods, such as increasing the reaction temperature, prolonging reaction residence time, and increasing CO2 and CH4 molar ratio, which could improve catalysts activity and stability. Besides, the positive effect of surface oxygen containing groups (C–O) on catalyst activity had been demonstrated over carbonaceous catalysts. The basic function of the carbonaceous materials surface area also seemed to increase H-abstraction of methane and CO2 adsorption. [Copyright &y& Elsevier]

Transition metal dichalcogenides have been the most attractive two-dimensional layered materials for electrocatalytic hydrogen evolution due to their unique structure and multi-phase electronic states. However, the enhancement of the WSe 2 electrocatalytic hydrogen evolution reaction (HER) performance by bimetal co-doping has been rarely reported. Herein, the NiMo-WSe 2 catalyst has been synthesized by a one-step hydrothermal reaction, with lower overpotentials of 177 and 188 mV at a current density of 10 mA cm -2 in 0.5 M H 2 SO 4 and 1 M KOH, respectively. The large specific surface area and thinner edge morphology provide more active sites for hydrogen production, thereby significantly improving the charge transfer kinetics. Density functional theory calculation results show that under acidic conditions the Δ G H* values of NiMo-WSe 2 with different structures and hydrogen adsorption sites are also different, when the hydrogen adsorption site was located at the top of the Se-Ni bond, the meta NiMo-WSe 2 has a Δ G H* value (-0.04 eV) that is closest to 0. Meanwhile, NiMo-WSe 2 ( meta ) also has a minimum of Δ G H* under alkaline conditions. DOS confirmed that Ni doping has a large impact on the electronic states at the WSe 2 Fermi level, while NiMo co-doping greatly reduces the potential energy barrier of the HER reaction, jointly increasing the current density, and thus improving the HER performance.