Atomic-level engineering Ni-N2O2 interfacial structure for enhanced CO2 electrocatalytic reduction efficiency.

The precise atomic-scale preparation of single-atomic active sites with unique coordination structures in electrocatalysts for the carbon dioxide reduction reaction (CO2RR), coupled with the elucidation of their mechanisms at the atomic level, remains a formidable challenge. In this manuscript, a simple one-pot synthesis method was adopted to successfully synthesize an O-doped Ni single-atom catalyst (Ni-NOG), characterized by a distinct Ni-N2O2 symmetric coordination structure. The incorporation of Ni-O bonds alters the electronic configuration of the catalyst's central atoms within the catalyst, thereby boosting both the catalytic selectivity and efficiency during CO2RR. The synthesized electrocatalyst exhibited outstanding performance in the CO2RR process, achieving a Faraday efficiency (FE) of 97.4 % at a potential of -0.8315 V versus to reversible hydrogen electrode (vs. RHE). Furthermore, the selectivity remained consistently above 95 % throughout a 98-hour stability test, surpassing the performance of most advanced catalysts currently available. Theoretical simulations demonstrate that the Ni-N2O2 symmetric coordination structure shows a small activation barrier in the rate-limiting step, favoring the swift generation of intermediate species and demonstrating robust catalytic activity. This work not only offers a straightforward and approach method for the preparation of single-atom catalysts but also clarifies the pivotal role of O-element doping within the coordination environment in enhancing catalyst performance.