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

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.