Zinc-phosphorus nanodomains with dynamic coordination for electrochemical CO2 reduction.

Single-atom catalysts (SACs) are favored owing to their well-defined motifs and notable CO selectivity in electrochemical CO2 reduction. However, the dynamic coordination evolution under working conditions and the structure-activity relationships remain highly puzzling. Herein, we suggest that flexible Zn-P3 nanodomains with weak-bond interactions may exhibit a potential-dependent structural modulation under working conditions compared to Zn-N4 configurations. A possible metastable state with reduced Zn-Px-like coordination may be formed from the Zn-P3 structure under CO2 reduction working conditions. Based on in situ spectroscopy analysis, deuterium isotope kinetic analysis, and theoretical calculations, the low-coordination Zn and the possibly perturbed P sites may serve as efficient active sites for the first step of sequential proton-electron transfer in the CO2 electroreduction. The collaborative assignments within this dynamic catalytic nanodomain, rather than at individual metal site, may contribute to the improved the intrinsic activity, which delivers a high turnover frequency (47,690 h-1) and a CO production rate (213 mL h-1 cm-2) at 500 mA cm-2 for 100 h. Our work elucidates the dynamic coordination-governed mechanisms of SACs and underscores the necessity of probing their structural basis under operating conditions.