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

Abstract

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.