Asymmetric Atomic Tin Catalysts with Tailored p‐Orbital Electron Structure for Ultra‐Efficient Oxygen Reduction

Abstract

AbstractAtomically dispersed transition metal–nitrogen–carbon (M–N–C) catalysts guide by the d‐band center theory have been extensively studied for oxygen reduction reaction (ORR) in various energy conversion and storage processes. However, asymmetric p‐block metal single‐atom catalysts (SACs) toward ORR have rarely been reported, and the origin of their catalytic activity is still unclear. Here, an asymmetric N, O coordinated Sn SAC is developed as an efficient ORR electrocatalyst. Remarkably, the optimized Sn SAC (e.g., Sn–N/O–C) exhibit outstanding ORR performance with a half‐wave potential of 0.910 V in alkaline media, outperforming most state‐of‐the‐art ORR catalysts. More importantly, the Sn–N/O–C possesses a long‐term durability in both alkaline and acidic electrolytes. Besides, Zn–air batteries based on the Sn–N/O–C cathode also show a higher energy density (254 mW cm‐2) than that of their reported M–N–C counterparts. Theoretical calculations suggest that the asymmetric N, O coordinated atomic Sn sites have a stronger binding interaction with O2 and better charge transfer ability compared with the symmetric SnN4 sites, thereby facilitating the ORR process. This work provides a nitrogen‐, oxygen‐coordinated engineering strategy for the rational design of highly active and durable carbon‐based catalysts with atomic p‐block metal sites for ORR and beyond.