New insight into catalytic performance and reaction mechanism for butyl acetate over CeO2 catalysts: Oxygen vacancy and surface reactive oxygen species

Revealing the relationship between the roles of reactive oxygen species in the oxidation process of butyl acetate from multiple perspectives is of great significance for better understanding the intrinsic mechanisms of the oxidation reactions. Oxygen vacancies, as important sites for gaseous oxygen adsorption and activation, are considered to be crucial for promoting the generation of surface reactive oxygen species. Herein, a series of CeO2 catalysts with different oxygen vacancy concentrations were synthesized for the oxidation of butyl acetate. Among all catalysts, the CeO2-U catalysts with fusiform morphology exhibited the highest oxygen vacancy concentration, which led to the generation of abundant reactive oxygen species on its surface. In particular, the in-situ DRIFTS studies dynamically revealed that the surface reactive oxygen species are beneficial for the rapid decomposition and oxidation of butyl acetate, as it promotes the breaking of butyl acetate C-O bonds and the formation of oxidized intermediate species. This contributed to the fact that CeO2-U exhibited the best catalytic activity in the oxidation reaction of butyl acetate, with T50 and T90 values as low as 184 degrees C and 199 degrees C, respectively. The findings of this study provide essential insights and references for understanding the mechanism of butyl acetate oxidation.