Highly Dispersed NiO Clusters Induced Electron Delocalization of Ni-N-C Catalysts for Enhanced CO2 Electroreduction

Oxygen-regulated Ni-based single-atom catalysts (SACs) show great potential in accelerating the kinetics of electrocatalytic CO2 reduction reaction (CO2RR). However, it remains a challenge to precisely control the coordination environment of Ni-O moieties and achieve high activity at high overpotentials. Herein, a facile carbonization coupled oxidation strategy is developed to mass produce NiO clusters-decorated Ni-N-C SACs that exhibit a high Faradaic efficiency of CO (maximum of 96.5%) over a wide potential range (-0.9 to -1.3 V versus reversible hydrogen electrode) and a high turnover frequency for CO production of 10 120 h(-1) even at the high overpotential of 1.19 V. Density functional theory calculations reveal that the highly dispersed NiO clusters induce electron delocalization of active sites and reduce the energy barriers for *COOH intermediates formation from CO2, leading to an enhanced reaction kinetics for CO production. This study opens a new universal pathway for the construction of oxygen-regulated metal-based SACs for various catalytic applications.