Electrochemical Reduction of CO 2 to CO over Transition Metal/N‐Doped Carbon Catalysts: The Active Sites and Reaction Mechanism

Electrochemical CO 2 reduction to value‐added chemicals/fuels provides a promising way to mitigate CO 2 emission and alleviate energy shortage. CO 2 ‐to‐CO conversion involves only two‐electron/proton transfer and thus is kinetically fast. Among the various developed CO 2 ‐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 CO 2 ‐to‐CO conversion is reviewed in detail. The regulation of the active sites in M‐N‐C catalysts and their related adjustable electrocatalytic CO 2 reduction performance is discussed. A visual performance comparison of M‐N‐C catalysts for CO 2 reduction reaction (CO 2 RR) 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 CO 2 to produce CO. Finally, outlooks and challenges are proposed for future research of CO 2 ‐to‐CO conversion.