Tracking the dynamics of catalytic Pt/CeO2 active sites during water-gas-shift reaction

Abstract

Understanding the atomistic structure of the active site during catalytic reactions is of paramount importance in both fundamental studies and practical applications, but such studies are challenging due to the complexity of heterogeneous systems. Here, we use Pt/CeO2 as an example to study the dynamic nature of active sites during the water-gas-shift reaction (WGSR) by combining multiple in situ characterization tools. We show that the different concentrations of interfacial Ptδ+ – O – Ce4+ moieties at Pt/CeO2 interfaces are responsible for the rank of catalytic performance of Pt/CeO2 catalysts: Pt/CeO2-rod > Pt/CeO2-cube > Pt/CeO2-oct. For all the catalysts, metallic Pt is formed during the WGSR, leading to the transformation of the active sites to Pt0 – Ov – Ce3+ and interface reconstruction. These findings shed light on the nature of the active site for the WGSR on Pt/CeO2 and highlight the importance of combining complementary in situ techniques for establishing structure-performance relationships. Understanding the atomic structure of active sites is important but challenging due to the complexity of heterogeneous systems. Here, the dynamic nature of Pt/CeO2 during the water-gas-shift reaction is studied using multiple in situ characterization tools to establish structure-performance relationships.