Low-coordination M–N3 active sites with high accessibility and efficiency for electrocatalytic O2 and CO2 reduction

Abstract

This review summarizes the methods to construct an efficient M–N₃ site-enriched porous structure with enhancement of the electrochemical accessibility. Compared with intact M–N₄, the low-coordination M–N₃ with defect-regulated geometry and high-density electronic structure is elaborated based on the recent progress of various electron beam-based techniques. The catalytic mechanism and the underlying structure–activity relationship of atomically dispersed M–N₃ reactive centers for the electrocatalytic oxygen reduction reaction and carbon dioxide reduction are well summarized. Finally, by highlighting the prospects and challenges for the development of defect-based single-atom catalysis, we hope to provide valuable insights for fabricating cost-effective SACs towards energy conversion.