Tailoring the interactions of heterogeneous Ag2S/Ag interface for efficient CO2 electroreduction

Electrochemical CO 2 reduction reaction (CO 2 RR) offers an appealing route to simultaneously store intermittent renewable energy as value-added chemicals and close carbon cycle. Silver (Ag) catalyst is a promising candidate for the electrochemical conversion of CO 2 to CO, but the electrocatalytic properties are still insufficient for practical applications. Herein, we put forward a strategy to in situ reconstruct a heterogeneous Ag 2 S/Ag interface structure, in which their strong interactions facilitate CO 2 RR performance. The in situ reconstructive Ag 2 S/Ag catalyst achieves a large current density of 421.7 ± 14.4 mA cm –2 at –0.70 V vs . reversible hydrogen electrode (RHE) and maintains steadily at a current density of 244.5 ± 31.8 mA cm –2 and CO Faradaic efficiency of 99.1 ± 0.8 % at –0.49 V vs . RHE for 50 h, superior to state-of-the-art CO-selective Ag-based catalysts. Density functional theory calculations reveal that the in situ reconstructive Ag 2 S/Ag interface active sites stabilize the *COOH intermediate during CO 2 RR process.