Understanding of Au-CeO2 interface and its role in catalytic oxidation of formaldehyde

To design an efficient catalyst for HCHO oxidation, it requires good understanding of the correlation between structural properties of catalyst and the reaction mechanism. We investigated performance of commercial CeO2 (CeO2-C) and nanorod CeO2 (CeO2-R) and the corresponding Au/CeO2 catalysts in HCHO oxidation. Reactivity tests showed that Au/CeO2-R is highly efficient and stable in HCHO oxidation at room temperature, which is attributed to the highly active Au-CeO2-R interface. The strong interaction between Au and CeO2-R greatly promotes the creation of oxygen vacancies and Au3+ near the interface, which promotes the formation of formate. The conversion of formate can follow both a decomposition and a direct oxidation pathway, which is remarkably enhanced by the coexistence of Au3+ and oxygen vacancies. In addition, formate accumulation and Au particles aggregation led to deactivation. The presence of humidity promotes the oxidation of formate, which improves the reactivity and stability of Au/CeO2 in HCHO oxidation.