Effects of Support on Performance of Methanol Oxidation over Palladium-Only Catalysts

摘要

Two kinds of palladium-only catalysts loaded mesoporous beta zeolite (Pd/beta) and alumina (Pd/Al2O3) have been successfully prepared by the impregnation method and characterized using nitrogen adsorption-desorption, XRD, TEM, H-2-TPR, CO2-TPD, and XPS. Catalytic activities of the catalysts for methanol oxidation were investigated with CO coexisting. The results showed that the different support determines the metal-support interaction, thus affecting the catalytic behavior. For Pd/beta, the strong basicity and better reductive ability are beneficial for improving the reaction rate of catalytic oxidation for methanol. And the palladium species with a higher oxidation state is responsible for excellent catalytic conversion of methanol and CO resistance. Compared to Pd/Al2O3, the T50, T90, and Delta T on Pd/beta catalyst are 145 degrees C, 160 degrees C, and 15 degrees C, respectively, in the case of CO present, which decreased by 45 degrees C, 91 degrees C, and 46 degrees C-. So beta zeolite, as a new type of catalyst support material, has a good application prospect to meet the practical needs for emission purification of methanol-gasoline vehicles.