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

Abstract Electrochemical CO2 reduction reaction (CO2RR) 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 CO2 to CO, but the electrocatalytic properties are still insufficient for practical applications. Herein, we put forward a strategy to in situ reconstruct a heterogeneous Ag2S/Ag interface structure, in which their strong interactions facilitate CO2RR performance. The in situ reconstructive Ag2S/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 Ag2S/Ag interface active sites stabilize the *COOH intermediate during CO2RR process.