Dynamic Structural Evolution of CeO2 in CuO-CeO2 Catalyst Revealed by In Situ Spectroscopy

The oxides and active metals at the interface synergistically activate reactants and thus promote the reaction, but the interface structure often changes dynamically during the reaction. In the conventional supported catalysts, the metals at the interface have been extensively studied, while the structural evolution of oxides is often overlooked due to the interference of the bulk phase signal. In this work, CeO2-CuO inverse catalysts are designed to reveal the dynamic structure evolution of CeO2 in the CeO2-CuO system during the water gas shift (WGS) reaction by in situ Raman, in situ XRD, quasi in situ XPS, and near ambient pressure XPS (NAP-XPS). CeO2 is partially concealed in the CuO phase in the un-pretreated catalyst and gradually exposed to the surface, forming an inverse CeOx/Cu structure during the reducing process. This structure exhibits a high catalytic activity in the WGS reaction and remains durable under the reductive conditions. When the inverse CeOx/Cu structure is exposed to the non-redox conditions, the reconfiguration of the reduced oxide is observed which is caused by the oxygen migration of CeO2. This work explores the structure evolution of CeO2 in CeO2-CuO inverse catalyst under different conditions by in situ characterization technique and provides a reference for monitoring the dynamic changes of oxide structure.

Automated summary

The structure evolution of CeO2 in CeO2-CuO inverse catalyst under different conditions is investigated using in situ characterization techniques, revealing the dynamic changes of CeO2 in the coexisting system and providing a reference for monitoring the dynamic changes of oxide structure.