Atomically Dispersed Manganese on Carbon Substrate for Aqueous and Aprotic CO₂ Electrochemical Reduction

Abstract CO₂ utilization and conversion are of great importance in alleviating the rising CO₂ concentration in the atmosphere. Here, a single‐atom catalyst (SAC) is reported for electrochemical CO₂ utilization in both aqueous and aprotic electrolytes. Specifically, atomically dispersed Mn–N₄ sites are embedded in bowl‐like mesoporous carbon particles with the functionalization of epoxy groups in the second coordination spheres. Theoretical calculations suggest that the epoxy groups near the Mn–N₄ site adjust the electronic structure of the catalyst with reduced reaction energy barriers for the electrocatalytic reduction of CO₂ to CO. The resultant Mn‐single‐atom carbon with N and O doped catalyst (MCs‐(N,O)) exhibits extraordinary electrocatalytic performance with a high CO faradaic efficiency of 94.5%, a high CO current density of 13.7 mA cm⁻², and a low overpotential of 0.44 V in the aqueous environment. Meanwhile, as a cathode catalyst for aprotic Li–CO₂ batteries, the MCs‐(N,O) with well‐regulated active sites and unique mesoporous bowl‐like morphology optimizes the nucleation behavior of discharge products. MCs‐(N,O)‐based batteries deliver a low overpotential and excellent cyclic stability of 1000 h. The findings in this work provide a new avenue to design and fabricate SACs for various electrochemical CO₂ utilization systems.