High-Performance Metal-Free Nitrogen-Doped Carbon Catalyst Derived from Polyurea–Polyimine Copolymer for Anion Exchange Membrane Fuel Cells

Developing cost-effective alternatives to platinum-based catalysts remains paramount for commercializing anion exchange membrane fuel cells (AEMFCs). We report a metal-free nitrogen-doped carbon catalyst derived from a rationally designed polyurea–polyimine copolymer that outperforms commercial 20 wt% Pt/C in superior relative durability and methanol tolerance. Strategic integration of polyurea’s pore-forming capability with polyimine’s thermal stability enabled the synthesis of a catalyst (NC-1000N) featuring ultrahigh surface area (1276.5 m2 g−1), optimal nitrogen speciation (20.5% pyridinic-N, 45.3% graphitic-N), and enhanced graphitization, which improves the electrical conductivity of catalysts. NC-1000N exhibited exceptional oxygen reduction performance with an onset potential of 0.96 V, almost four-electron selectivity (n = 3.87), a medium Tafel slope (105 mV dec−1), and minimal charge transfer resistance (46.74 Ω). When evaluated in single-cell AEMFCs, NC-1000N delivered a peak power density of 372.1 mW cm−2, which is 26% higher than Pt/C at equivalent loading, while demonstrating superior stability (94.8% retention after 7 h) and complete methanol tolerance. Systematic pyrolysis temperature optimization (800–1000 °C) revealed critical structure–property relationships governing catalyst evolution from disordered precursor to highly graphitic, nitrogen-enriched carbon with precisely engineered active sites. This work establishes polymer-derived carbons and provides design principles for scalable synthesis of high-performance metal-free electrocatalysts for sustainable energy conversion technologies.