Carbon material with high pyridine/graphite nitrogen content: an efficient electrocatalyst for the oxygen reduction reaction

Zn-air batteries have garnered significant interest due to their high capacity, economical cost, and eco-friendly nature. The pursuit of non-noble metal cathode catalysts that offer high activity, exceptional durability, and cost-efficiency as alternatives to noble metal platinum is a prominent research focus. In this investigation, a nitrogen-doped carbon material predominantly constituted of pyridinic nitrogen and graphitic nitrogen was synthesized utilizing the polymer of hexaaminobenzene and hexaketocyclohexane as precursors. In a 0.1 M KOH electrolyte, this catalyst demonstrated ORR catalytic activity on par with commercial Pt/C and showcased enhanced stability compared to Pt/C. When incorporated as a cathode catalyst in a zinc-air battery, the battery exhibited stable discharge for 95 hours at a current density of 5 mA cm-2, achieving a specific capacity as high as 730 mA h g-1. Its discharge efficacy remained consistent even following multiple replacements of the anode zinc plate, facilitating the repeated use of the zinc-air battery. This research underpins the technical foundation and theoretical framework for the advancement of novel carbon-based catalysts characterized by straightforward production techniques, affordability, and superior activity and resilience. Polymers with a high C/N ratio were synthesized by a simple solvolysis method and carbonized to obtain a CN-800 catalyst rich in pyridine-N and graphite-N, which exhibited significant ORR activity and stability.