Boosting CO2 electroreduction to CO with abundant nickel single atom active sites†

The conversion of CO2 into value-added chemicals through the electrocatalytic CO2 reduction reaction (CO2RR) is considered as an up-and-coming way to facilitate the renewable closed carbon cycle and energy storage. Therefore, the development of robust and low-cost CO2RR electrocatalysts is essential but challenging. Herein, a Ni single-atom catalyst (Ni-SAs-NC) was successfully prepared via a precursor assembly strategy and a subsequent one-step pyrolysis process. Characterization studies demonstrate that abundant Ni single-atom active sites with the coordination structure of Ni-N-4 are uniformly dispersed in Ni-SAs-NC, which consequently endow it with outstanding electrocatalytic CO2RR performance. Strikingly, the as-prepared Ni-SAs-NC can selectively convert CO2 into CO with a high faradaic efficiency of up to 98%, and can maintain the high values exceeding 90% in a wide potential range from -0.6 to -1.0 V. This work provides a new protocol to prepare high-efficiency but low-cost single-atom electrocatalysts toward the CO2RR and other electrochemical reactions.