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.