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-Ce_0.6Zr_0.4O₂ 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 PdO_x and CeO₂ after hydrogen pretreatment. It was confirmed by XPS analysis, and the generation of higher charged Pd^δ+ (δ > 2) species were discovered. As a result, it was induced that the presence of stronger interactions between PdO_x and CeO₂ after prereduction mainly contributes to the remarkably enhanced activity.