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

CO utilization and conversion are of great importance in alleviating the rising CO concentration in the atmosphere. Here, a single-atom catalyst (SAC) is reported for electrochemical CO utilization in both aqueous and aprotic electrolytes. Specifically, atomically dispersed Mn-N 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-N site adjust the electronic structure of the catalyst with reduced reaction energy barriers for the electrocatalytic reduction of CO 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 , and a low overpotential of 0.44 V in the aqueous environment. Meanwhile, as a cathode catalyst for aprotic Li-CO 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 CO utilization systems.