The electrochemical carbon dioxide reduction reaction (CO2RR) offers a route to store renewable electricity as value-added chemicals. However, designing electrocatalysts with high selectivity and stability remains a significant challenge. Here, an elaborate catalyst, AuCu1 supported on polypyrrole (defined as AuCu1/PPy), synthesized via an electrodeposition-galvanic replacement reaction, featuring d–π conjugation, demonstrates exceptional performance for CO2-to-CO conversion. With atomically isolated Cu sites confirmed by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray absorption spectroscopy, the AuCu1/PPy catalyst modulates both electronic configuration and spatial immobilization of Au active sites, yielding 99.16% CO faradaic efficiency (FE) with sustained stability over 30 h at −0.6 V versus the reversible hydrogen electrode (RHE), representing 1.83-fold and 8.57-fold improvements in FE and stability compared to the control catalyst Au/PPy. In situ Raman experiments and density functional theory calculations reveal that isolated Cu promotes uniform Au growth, further modulating and stabilizing the *CO2–/*COOH intermediate adsorption via d–π conjugation. Concurrently, the delocalized electronic structure enhances charge transfer, lowering activation barriers for *CO formation by 58%. Critically, d–π conjugation regulates electronic and geometric structures of Au nanoparticles, reducing the energy barrier to superior selectivity and durability. This work constructs a metal-coupled polymer electrocatalyst to decipher the mechanistic role of d–π conjugation in the CO2RR, which may provide new insights for the rational design of advanced catalysts.
Gao et al. (Mon,) studied this question.