Hexamine-Coordination-Framework-Derived Co–N-doped Carbon Nanosheets for Robust Oxygen Reduction Reaction

In this work, Co–N-doped carbon nanosheet (Co-NCS), obtained through a self-assembly strategy and subsequent pyrolysis process, was reported as an efficient ORR catalyst. Combining the unique 2D architecture and high N-doping level, the optimized Co-NCS exhibits a superior ORR performance with more positive onset potential (0.96 V) and half-wave potential (0.93 V) than those of commercial Pt/C under alkaline conditions. Additionally, the optimized catalyst also displays desirable ORR activity in acidic media, approaching that of commercial Pt/C. Significantly, the synergistic catalysis is demonstrated through selective etching of active species, holding great potential in an in-depth understanding of the contributions of CoN x and Co@C NPs in catalysts. Furthermore, the zinc–air batteries assembled with the optimized Co-NCS as the air cathode outperform the Pt-based zinc–air batteries. This finding sheds light on the synthesis of ORR catalysts and the exploration of their application in energy conversion systems.