CuO-In2O3 collaboration in CO2 electroreduction: Enhanced activity and synergistic mechanism

The conversion of CO2 into high value-added products via electrocatalytic technology is one of the most attractive methods of addressing the ecological crisis and achieving carbon neutrality. In this study, we present CuO-In2O3 nanosheets with bifunctional active components for the efficient electrochemical reduction of CO2 to CO. The catalyst demonstrates a current density of 35.3 mA cm- 2 with a high faradic efficiency of 97.3 % toward CO at - 0.6 V versus the reversible hydrogen electrode. In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy and density functional theory calculations reveal that the synergistic catalysis of CuO and In2O3 rationally balances the binding energy to *COOH and *CO intermediates. It promotes the catalyst selectivity for CO. Furthermore, CuO and In2O3 play key roles as bifunctional active sites. In particular, CuO enhances the activity of CO2 and reduces the formation energy barrier of the reaction intermediates, whereas In2O3 suppresses the adsorption of *H and limits the hydrogen evolution reaction.