Epoxides as the Gateway to High-Level Nitrogen Incorporation in Graphene Oxide

Abstract Nitrogen-doped graphene holds immense promise for electrocatalysis, where surpassing the traditional 2–5 at% nitrogenation ceiling requires strategic control of thermodynamic and kinetic factors. Here, we systematically investigate the dominant thermodynamic and kinetic parameters to reach higher nitrogenation. It is demonstrated that, within the investigated 140–200 °C hydrothermal regime, neither kinetic nor mass-transport limitations matter, in sharp contrast to the prevailing literature. Instead, nitrogenation levels are fundamentally governed by the population of basal-plane epoxide groups, meaning that the starting graphene oxide oxidation degree alone limits ultimate doping efficiency. Optimizing precursor oxidation successfully drives the final nitrogen content to 17.3 at% (N/C = 0.24). Subsequent thermal treatment efficiently converts this grafted nitrogen into lattice-doped configurations dominated by pyridinic N (57%). This work establishes a framework showing that maximizing reactive oxygen sites is the definitive pathway to advanced nitrogen-doped frameworks.