Syntheses and applications of single-atom catalysts for electrochemical energy conversion reactions

Singe-atom catalysts (SACs), as heterogeneous catalysts, have attracted increasing attention in recent years owing to their numerous advantages in the field of electrocatalysis, such as a high atom-utilization rate and unique structural characteristics. In this review, we introduce various preparation methods for obtaining SACs based on top-down and bottom-up synthesis strategies and the corresponding research progress made in recent years. We also focus on the electrocatalytic applications of SACs containing noble metals (Pt, Pd, Ir, etc.) and non-noble metals (Fe, Cu, Co, etc.) in the oxygen evolution reaction, hydrogen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and nitrogen reduction reaction. Finally, the future challenges and prospects of monatomic catalysts are also discussed.