RESUMO
The direct oxidation of methane to methanol under mild conditions is challenging owing to its inadequate activity and low selectivity. A key objective is improving the selective oxidation of the first carbon-hydrogen bond of methane, while inhibiting the oxidation of the remaining carbon-hydrogen bonds to ensure high yield and selectivity of methanol. Here we design ultrathin PdxAuy nanosheets and revealed a volcano-type relationship between the binding strength of hydroxyl radical on the catalyst surface and catalytic performance using experimental and density functional theory results. Our investigations indicate a trade-off relationship between the reaction-triggering and reaction-conversion steps in the reaction process. The optimized Pd3Au1 nanosheets exhibits a methanol production rate of 147.8 millimoles per gram of Pd per hour, with a selectivity of 98% at 70 °C, representing one of the most efficient catalysts for the direct oxidation of methane to methanol.
RESUMO
Tremella-like V2O5 microspheres were successfully synthesized in this study through a facile hydrothermal method. The microstructures and electrochemical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) measurements and galvanostatic charge-discharge tests. V2O5 microspheres with unique tremella-like structure exhibited good reversible capacity, with an initial discharge capacity of 147 mA·h·g-1 at 1 C rate. Moreover, the capacity retention rate was 91.36% and charge-discharge efficiency was still over 98% after 400 cycles. Such outstanding properties can be ascribed to their unique tremella-like structure.