Strong oxide-support interaction (SOSI) plays a crucial role in the catalytic performance of heterogeneous oxide catalysts, but the underlying mechanism to understand dynamic behaviors of interface and tune its catalytic activity are still unspecified. Here, we report the first evidence of SOSI between In2O3 catalyst and TiO2 support based on the results of in situ spectroscopic characterizations. Under the influence of SOSI, the reverse water gas shift (RWGS) reaction can induce the migration of In2O3 from nanoparticle to nanolayer on the TiO2 surface, where the dispersion capacity of In2O3 is about 0.07 g In2O3/100 m2 TiO2. This dynamic structure evolution of surface enables the electron transfer between In2O3 and TiO2, resulting in the facile formation of oxygen vacancies in In2O3 while difficult reduction from dispersed In2O3 to In (0). Those significant changes on surface chemical properties of In2O3 led to its high catalytic activity and stability. In situ XRD and XPS analyses suggest In (0), instead of InOx, is the intermediate in the migration of In2O3 on TiO2 during the RWGS reaction. Dispersion and aggregation state of In2O3 can be controlled by using an oxidizing-reducing atmosphere cycle. The reduction of H2 facilitates the dispersion of In2O3 on the surface of TiO2, while the oxidizing atmosphere led to the aggregation of In2O3 nanolayers. These findings highlight the importance of SOSI in catalytic reactions and provide a new insight for understanding and designing heterogeneous catalysts.

Reaction induced strong oxide-support interaction in supported oxide catalysts for enhanced catalysis

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