Atomic-Dispersed Coordinated Unsaturated Nickel–Nitrogen Sites in Hollow Carbon Spheres for the Efficient Electrochemical CO2 Reduction

Reducing carbon dioxide to high value-added chemicals is of high importance due to its vital role in mitigating CO 2 emission and energy crisis. However, seeking for robust catalysts with low overpotential, high selectivity, and stability is extremely challenging. Herein, a single Ni atom anchored on an N-doped carbon (Ni–N–C) catalyst was designed and prepared via a facile synthesis method to embed highly and evenly dispersed, coordinated unsaturated nickel–nitrogen active sites into a hollow carbon matrix with abundant micropores. The prepared Ni–N–C catalysts possess a unique electronic structure, coordination environment, and maximized atomic utilization, which accordingly show a higher intrinsic activity and remarkable selectivity for the electrochemical reduction of CO 2 . Additionally, the coordination structure and content of Ni can be easily modulated by changing the calcination temperature, which plays a vital role for the catalytical performance. As a result, the Ni–N–C catalysts achieve over 90% for CO at a wide potential window from −0.6 to −1.0 V with a maximum value of 97% at −0.8 V. This paper paves a facile way to develop high-performance single atomic catalysts with a tunable Ni–N coordination structure for CO 2 reduction.