Nitrogen-rich carbon-based materials are amongst the most promising electrocatalysts for the oxygen reduction reaction (ORR) and/or the oxygen evolution reaction (OER). The introduction of nitrogen within the carbonaceous framework generates catalytic active sites and alters the electrical conductivity. However, the synthesis of these materials often involves long processes and severe reaction conditions which yield a low concentration of nitrogen (N) functionalities. Herein, we present a facile method for the synthesis of N-rich carbon by carbonizing a carbon nitride (C3N4)-polydopamine composite (CNDA) which can readily be prepared by room temperature self-polymerisation of dopamine in the presence of C3N4. The intrinsically high N content in C3N4 leads to a highly N-doped carbon. The CNDA catalyst synthesized at 900 °C contained 12.5 at% of N, enhancing both the ORR and OER catalytic activities through a 4-e− dominated pathway, providing a comparable E1/2 and a remarkably improved diffusion-limited current to the other reported N-doped carbon catalysts. When used as an air-cathode in a zinc-air battery, this CNDA catalyst possessed stable discharge-charge cycling performance for 216 h, outperforming the Pt/C standard. This work opens a promising platform for the development of template-free processes for the synthesis of non-metal and nitrogen-rich carbon materials which are attractive for metal-air batteries and fuel cells
