Highly efficient Pd/Al2O3-Ce0.6Zr0.4O2 catalyst pretreated by H2 for low-temperature methanol oxidation

Abstract

We report an interesting finding that the catalytic performance of Pd/Al2O3-Ce0.6Zr0.4O2 catalyst toward complete oxidation of methanol at low temperature could be greatly enhanced by prereduction in hydrogen. The light-off temperature (T50) could be reached rapidly at 67 °C. TPR patterns showed that the reducibility is highly increased due to the formation of stronger interactions between PdOx and CeO2 after hydrogen pretreatment. It was confirmed by XPS analysis, and the generation of higher charged Pdδ+ (δ > 2) species were discovered. As a result, it was induced that the presence of stronger interactions between PdOx and CeO2 after prereduction mainly contributes to the remarkably enhanced activity.