Hf and Co Dual Single Atoms Co‐Doped Carbon Catalyst Enhance the Oxygen Reduction Performance

Abstract

AbstractSingle‐atom metal‐doped M–N–C (M═Fe, Co, Mn, or Ni) catalysts exhibit excellent catalytic activity toward oxygen reduction reactions (ORR). However, their performance still has a large gap considering the demand for their practical applications. This study reports a high‐performance dual single‐atom doped carbon catalyst (HfCo–N–C), which is prepared by pyrolyzing Co and Hf co‐doped ZIF‐8 . Co and Hf are atomically dispersed in the carbon framework and coordinated with N to form Co–N4 and Hf–N4 active moieties. The synergetic effect between Co–N4 and Hf–N4 significantly enhance the catalytic activity and durability of the catalyst. In an acidic medium, the ORR half‐wave potential (E1/2) of the catalyst is up to 0.82 V , which is much higher than that of the Co–N–C catalyst without Hf co‐doping (0.80 V). The kinetic current density of the catalyst is up to 2.49 A cm−2 at 0.85 V , which is 1.74 times that of the Co–N–C catalyst without Hf co‐doping. Moreover, the catalyst exhibits excellent cathodic performance in single proton exchange membrane fuel cells and Zn–air batteries. Furthermore, Hf co‐doping can effectively suppress the formation of H2O2, resulting in significantly improved stability and durability.