Insights into CO Oxidation in Cu/CeO2 Catalysts: O2 Activation at the Dual-Interfacial Sites

Cu clusters supported on CeO₂ have been reported as a promising and active catalyst for CO oxidation. However, the identification of interfacial interactions and active sites is still a great challenge. In this work, we demonstrated that interfacial chemistry can be understood and predicted by using a simple descriptor of adsorbate-surface interactions that uncovers structure-activity relationships. The catalytic activity of CeO₂ supported Cu clusters for CO oxidation was studied by density functional theory. The Cu−Ce dual site mechanism enables the Cu/CeO₂ catalyst to have a much lower reaction energy barrier than the Mars-van Krevelen (M-vK) mechanism and the Cu-only mechanism. The reaction energy barriers of Cu/CeO_2-x with an oxygen vacancy on the CeO₂ surface were 0.10, 0.37 and 0.77 eV, respectively. The excellent performance of Cu/CeO₂ catalysts is related to the interfacial interaction between Cu and CeO₂ and their synergistic redox behaviors, and oxygen vacancies facilitate the generation and stabilization of active Cu⁺ species through the interaction with Cu clusters. And we have identified the binding energy of O₂* can describe the CO oxidation activity of Cu/CeO₂. Our study provides insight into the nature of active sites for Cu/CeO₂ catalysts and guidance for high-performance.