Transition Metal‐Nitrogen‐Carbon Single‐Atom Catalysts Enhanced CO2 Electroreduction Reaction: A Review

As the global energy crisis and environmental challenges worsen, CO2 conversion has emerged as a focal point in international research. CO2 electroreduction reaction (CO2ER) is a green and sustainable technology that converts CO2 into high‐value chemicals, thereby achieving the recycling of carbon resources. However, the activity and selectivity are constrained by the performance of the catalyst. Although traditional N‐doped carbon‐based catalysts exhibit excellent performance toward CO2ER, the atomic utilization rate in these materials is far from 100%. Single atom catalysts (SACs) can attain nearly 100% atomic utilization efficiency because of the fully exposing metal atoms. Therefore, SACs have emerged as one of the hot research materials in the field of CO2ER. Recently, transition metal‐nitrogen‐carbon single‐atom catalysts (TM‐N‐C SACs) have flourished because of their extraordinary catalytic activity, low cost, and excellent stability, demonstrating enormous application prospects in CO2ER. In this review, we concentrate on TM‐N‐C SACs that electrochemically reduce CO2 to high value products. A comprehensive and detailed discussion were conducted on the synthesis method, chemical structure, chemical characterization of TM‐N‐C SACs, as well as their catalytic performance, active sources, and mechanism exploration for CO2ER. Finally, challenges and prospects for commercial application of TM‐N‐C SACs catalysts suitable for CO2ER are proposed.