A dual-coordination strategy to construct mesoporous carbon-dominated Fe-NC catalysts for fuel cells with enhanced durability

Iron-nitrogen-carbon (Fe-NC) materials have emerged as leading candidates among non-precious metal catalysts for the oxygen reduction reaction, offering a potential replacement for platinum-group metals in proton exchange membrane fuel cells (PEMFCs). However, the high intrinsic activity of current Fe-NC catalysts is often accompanied by rapid degradation, primarily due to the prevalence of M-N x active sites embedded within microporous carbon frameworks, which exhibit limited resistance to demetallation. Here, we report the development of mesoporous carbon-dominated Fe-NC (MC-Fe-NC) catalysts featuring atomically dispersed Fe-N 4 active sites (5.62×10 19 sites g −1 ), synthesized via a dual-coordination strategy combined with an assisted in-situ pore-forming approach. Mechanistic investigations reveal that the interconnected mesoporous architecture improves mass transport and water management at the electrode/membrane electrode assembly level, thereby mitigating carbon corrosion and structural degradation during durability testing. MC-Fe-NC demonstrates superior durability under stringent H 2 /air conditions, retaining 82% of initial current density at 0.6 V for 36 h, 92% of initial voltage at 0.2 A cm −2 for 100 h and enduring 30000 square-wave voltage cycles—surpassing the performance of most previously reported Fe-NC systems. Distribution of relaxation time analysis further supports that the mesoporous structure alleviates water flooding and carbon corrosion-related transport deterioration. Density functional theory calculations reveal that the N-enriched local coordination environment downshifts the d -band center, weakens OH-related perturbations, and reduces the driving force for metal dissolution, thereby enhancing the intrinsic anti-dissolution capability of the active sites. These results indicate that the improved durability originates from the synergistic effect of the interconnected mesoporous architecture and the N-enriched local coordination environment. This work offers a rational design pathway for stabilizing single-atom catalytic sites through the optimization of mesoporous structure and local coordination environment, advancing the practical deployment of non-precious metal catalysts in PEMFCs.