Electrochemical Reduction of CO₂ to CO over Transition Metal/N-Doped Carbon Catalysts: The Active Sites and Reaction Mechanism

Electrochemical CO₂ reduction to value-added chemicals/fuels provides a promising way to mitigate CO₂ emission and alleviate energy shortage. CO₂-to-CO conversion involves only two-electron/proton transfer and thus is kinetically fast. Among the various developed CO₂-to-CO reduction electrocatalysts, transition metal/N-doped carbon (M-N-C) catalysts are attractive due to their low cost and high activity. In this work, recent progress on the development of M-N-C catalysts for electrochemical CO₂-to-CO conversion is reviewed in detail. The regulation of the active sites in M-N-C catalysts and their related adjustable electrocatalytic CO₂ reduction performance is discussed. A visual performance comparison of M-N-C catalysts for CO₂ reduction reaction (CO₂RR) reported over the recent years is given, which suggests that Ni and Fe-N-C catalysts are the most promising candidates for large-scale reduction of CO₂ to produce CO. Finally, outlooks and challenges are proposed for future research of CO₂-to-CO conversion. © 2021 The Authors. Advanced Science published by Wiley-VCH GmbH