Plasma-assisted and oxygen vacancy-engineered In2O3 films for enhanced electrochemical reduction of CO2

Abstract Oxygen vacancy-enriched In2O3 nanomaterials are promising catalysts for electrocatalytic CO2 reduction owing to their excellent capability to activate CO2 during catalysis. Despite substantial progress, facile and controllable methods for oxygen vacancy construction require further exploration. Herein, magnetron sputtering is used for generating oxygen vacancies in In2O3 films with the help of high-energy plasma treatment. A series of In2O3 films were prepared through magnetron sputtering at different oxygen partial pressures, and the In2O3 sample without oxygen partial pressure exhibited excellent performance in HCOOH production. The large yield of C1 products is mainly attributed to the increased surface electronic density according to density functional theory (DFT) calculations. The DFT results indicated that the reaction proceeded with *COOH obtained as the intermediate, and the formation barrier of *COOH decreased with an increase in oxygen vacancies. The present route provided a novel and convenient strategy for developing defect-rich catalysts for electrochemical CO2RR.