Pyrrolidone-Bridged Ag-Cu2O Heterointerfaces Enable Selective C-C Coupling for Efficient Electrochemical CO2 Reduction.

Cu2O-derived catalysts are promising for electrochemical CO2 reduction (CO2RR) because Cu+ sites and dynamically reconstructed Cu+/Cu0 interfaces can stabilize CO-derived intermediates and facilitate C-C coupling toward C2+ products. However, their C2+ selectivity remains limited despite advances in morphology and surface engineering. Here, we propose a dual-modification strategy by co-engineering Cu2O with Ag and polyvinylpyrrolidone (PVP). Ag increases local CO coverage, while PVP modulates the electronic structure of Cu/Ag sites, jointly promoting C-C coupling. This synergistic interface establishes a locally alkaline, carbonate-rich microenvironment that facilitates dual hydrogen-source utilization and enhances ethanol production. The catalyst achieves Faradaic efficiencies of 52.2% for ethanol and 72.2% for total C2 products, with stable operation over 12 h. In situ X-ray absorption spectroscopy reveals partial recovery of Cu+ via Ag-PVP coupling during electrolysis, while in situ Raman spectroscopy confirms a shift from bicarbonate to carbonate-dominated interfacial chemistry. These results demonstrate that coordinated electronic and microenvironmental regulation effectively overcomes key limitations in Cu2O-based CO2RR, providing a rational design strategy for high-performance C2+-selective electrocatalysts.