State-of-the-art single-atom catalysts in electrocatalysis: From fundamentals to applications

Metal single-atom catalysts are becoming very popular owing to their remarkable and fascinating atomic-scale utilization efficiency, electrocatalytic activity, and selectivity. Because of their compositional and structural tunability, as well as their unique electronic nature, single-atom catalysts (SACs) are promising new types of catalytic materials. Extensive research is being conducted to design and develop highly efficient SACs for various electrocatalytic applications. This review aims to provide a thorough understanding of the fundamentals, challenges and activity improvement strategies of SACs. Further, this review summarizes the recent advances in the design and development of SACs for applications in electrocatalysis. The diverse utilization of SACs in electrocatalysis is discussed through the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), and nitrogen reduction reaction (NRR). Besides, the basic mechanisms and applications of SACs in electrocatalysis are discussed in detail. In addition, prospects for improving SACs activity and selectivity are also thoroughly discussed.