Dynamic reconstruction of Cu-doped SnO2 for efficient electrochemical reduction of CO2 to formate

Electrochemical reduction of CO2 to value-added chemicals and fuels is an attractive strategy to address global warming and reduce energy consumption. Here, Cu-doped SnO2 that undergoes in situ reconstruction to form catalytically active Cu/Sn alloys was synthesized at cathodic potentials during CO2 reduction reactions (CO2RR). The Cu-doped SnO2 exhibited a remarkable formate Faradaic efficiency of over 90 % and maintained stability for 12 h. Notably, a formate current density of 220 mA cm(-2) was achieved in a flow cell. Density functional theory (DFT) calculations on the resulting Cu/Sn catalysts revealed that the generated Cu/Sn alloy enhances formate production by optimizing the binding of the reaction intermediate *OCHO. Additionally, it promotes the Faradaic efficiency of formate products by suppressing the competitive CO2RR with CO and hydrogen evolution reactions, thereby leading to high Faradaic efficiency and current density in CO2RR.