Role of Interfacial Cu‐Ions in Polycrystalline Cu‐CeO 2 : In‐Situ Raman, In‐situ DRIFT and DFT Studies for Preferential Oxidation of CO in Presence of Excess H 2 **

Abstract In this work, we designed a polycrystalline Cu‐CeO 2 catalyst with defect sites, and it has superior CO oxidation activity in presence of excess H 2 . The oxygen defects of Cu‐CeO 2 influence the adsorption of unalike surface di ‐ oxygen types, and the catalyst was characterized through XRD (X‐Ray Diffraction) analysis, TEM (Transmission electron microscopy), in ‐ situ Raman spectroscopy, in ‐ situ DRIFT (Diffuse reflectance infrared fourier transform) spectroscopy. TEM showed that CeO 2 (111) plane are the exposed plane for this reaction. Raman spectroscopy showed nature of the defects of the prepared catalyst and how it works in the reaction environment. In‐situ DRIFT spectroscopy showed that the Cu + ↔Cu 2+ system is working in this reaction environment. Role of interfacial Cu ions was confirmed by in‐situ DRIFT spectroscopy and DFT (Density functional theory) study.