Optimizing the Electrocatalytic Selectivity of Carbon Dioxide Reduction Reaction by Regulating the Electronic Structure of Single-Atom M-N-C Materials

Electrochemical carbon dioxide reduction reaction (CO2RR) is an efficient strategy to relieve global environmental and energy issues by converting excess CO2 from the atmosphere to value-added products. Atomically dispersed metal-nitrogen-doped carbon (M-N-C) materials are superior catalysts for electrocatalytic CO2RR because of the 100% atomic utilization, unsaturated coordination configuration, relatively uniform active sites, and well-defined and adjustable structure of active centers. However, the electrochemical CO2RR is a great challenge due to the process involving proton-coupled multi-electron transfer with a high energy barrier, which leads to unsatisfactory selectivity to the targeted product, especially for C2 products (e.g., C2H4 and C2H5OH). Here, the authors systematically summarize effective means, including reasonable selection of isolated metal sites, regulation of the coordination environment of isolated metal atoms, and fabrication of dimetallic single-atom sites for attaining optimal geometric and electronic structures of M-N-C materials and further correlate these structures with catalytic selectivity to various C1 (e.g., CO and CH4) and C2 products in the CO2RR. Moreover, constructive strategies to further optimize M-N-C materials for electrocatalytic CO2RR are provided. Finally, the challenges and future research directions of the application of M-N-C materials for electrocatalytic CO2RR are proposed.

Automated summary

Electrochemical carbon dioxide reduction reaction (CO2RR) is an efficient strategy to convert excess CO2 to value-added products. Atomically dispersed metal-nitrogen-doped carbon (M-N-C) materials are superior catalysts for CO2RR due to their unique structures. However, CO2RR is challenging due to the high energy barrier involved.