Metal-support interaction (MSI) provides great possibilities to tune the activity, selectivity, and stability of heterogeneous catalysts. Herein, the Au/ZnO catalyst is prepared by commercial ZnO and chloroauric acid, and the structure evolution of the catalyst pretreated by H and O gas at varied temperature is investigated to provide mechanistic insights of MSI. It is found that the H treatment at 300 °C and above can induce the formation of both the ZnO overlayer and bulk Au-Zn alloy. In contrast, the O treatment can form the ZnO overlayer at 500 °C and above without the formation of Au-Zn alloy. It is also revealed that the ZnO overlayer is dynamically stable (permeable), which can provide access for reactant molecules during the reaction process. And, the Au-Zn alloy can recover to Au and ZnO under the CO oxidation reaction condition, which can be deemed as a re-activation process that endows H -treated samples with the superior activity and stability.
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