Boosting Electrochemical Reduction of CO₂ to Formate over Oxygen Vacancy Stabilized Copper–Tin Dual Single Atoms Catalysts

Abstract Designing reasonable atomic structures is essential in modulating the selectivity of the valuable products produced in the electrochemical CO₂ reduction. Herein, a CuSn diatomic sites electrocatalyst stabilized by double oxygen vacancies on CeO_2‐x is constructed, which exhibits superior electrochemical selectivity toward formate, achieving a 90.0% Faradaic efficiency at formate partial current density of 216.8 mA cm⁻² with the applied bias of −1.2 V versus REH. The experimental characterizations and theoretical calculations highlight the significance of the synergistic effect of Cu and Sn diatoms on reducing the activation energy and promoting the formation of intermediate ^*OCHO, which accounts for its high selectivity toward formate. Meanwhile, the oxygen vacancies on the CeO_2‐x also play a pivotal role in manipulating the electrochemical performance and stability, which underlines the importance of regulating the electronic metal‐support interaction between CuSn diatoms and CeO_2‐x. This work demonstrates an effective method to design efficient electrochemical CO₂ reduction catalysts by modulating the surface structures of single‐atoms anchored support.