One pot solvent assisted syntheses of Ag3SbS3 nanocrystals and exploring their phase dependent electrochemical behavior toward oxygen reduction reaction and visible light induced methanol oxidation reaction

Strategically Designed Pd-Induced Changes in Alkaline Hydrogen Evolution Reaction and Oxygen Evolution Reaction Performances of Electrochemical Water Oxidation by the Galvanically Synthesized MoO2/MoO3 Composite Thin Film

Electrochemical water oxidation is believed to be an effective pathway to produce clean, carbon-free, and environmentally sustainable green energy. In this work, we report a simple, easy-to-construct, facile, low-cost, and single-step galvanic technique to synthesize a Pd-supported temperature-assisted MoOx thin film nanocomposite for effective water oxidation. The most suitable nanocomposite exhibits very low overpotential at 10 mA/cm2 with smaller Tafel slope values for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) processes in an alkaline medium. The formation of a metal oxide-metal junction accelerates the growth of more active sites, promoting induced electronic synergism at the MoOx-Pd interface. This endows higher electrical conductivity and faster electron transfer kinetics, thus accelerating the faster water dissociation reaction following the Tafel-Volmer mechanism to boost the HER process in an alkaline medium. The excellent electrochemical HER and OER performances of our electrocatalyst even supersede the accomplishments of the benchmark catalysts Pt/C and RuO2. Moreover, neither of these two catalysts demonstrates both catalytic reactions, i.e., HER and OER at the same time, which have been observed for our synthesized catalyst. Our findings illustrate the potential of a thin-film MoOx-Pd nanocomposite to be an exceedingly effective electrocatalyst developed by interface engineering strategies. This also provides insight into designing several other semiconductor composite catalysts using simple synthesis techniques for highly efficient HER/OER processes that could be alternatives to benchmark electrocatalysts for water electrolysis.

Effect of modified CeO2 on the performance of PdCu/Ce1-xTixO2 catalyst for methanol purification

In this paper, we prepared a series of Ce_1-xTi_xO₂ (x = 0-0.20) nanorods by hydrothermal method, which were used to construct the PdCu/Ce_1-xTi_xO₂ catalysts. The Ce_1-xTi_xO₂ and PdCu/Ce_1-xTi_xO₂ samples were characterized by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N₂ adsorption-desorption, X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), etc. Catalytic activity, stability, and repeatability of the catalysts for methanol oxidation were investigated. The results show that doping a proper amount of titanium could strengthen the interaction between Ce_1-xTi_xO₂ support and PdCu nanoalloy, thus increasing the oxygen vacancy concentration and promoting Pd species with a higher oxidation state. These modified properties are beneficial for the deep oxidation of methanol. The light-off temperature (T₅₀) and full-conversion temperature (T₉₀) of methanol over the PdCu/CeO₂ catalyst are 108 °C and 159 °C, respectively. The greatest activity improvement is found for PdCu/Ce_0.9Ti_0.1O₂, which shows the lowest T₅₀ of 88 °C and T₉₀ of 138 °C. Furthermore, neither PdCu/CeO₂ nor the modified PdCu/CeO₂ catalyst produces by-products and exhibit excellent stability and repeatability throughout the whole test period. This study provides a reference for in-depth understanding and designing of efficient and stable CeO₂-based oxidation catalysts.