Dual-nitrogen coordination engineering enables porous carbon-confined Pt-FeN4 atomic interfaces for durable, low-Pt PEM fuel cells

Abstract

Designing low-Pt catalysts with both high intrinsic activity and long-term durability remains a central challenge for proton exchange membrane fuel cells (PEMFCs). Here, we report a dual-nitrogen coordination strategy that simultaneously optimizes the electronic structure and structural stability of Pt/Fe-N-C catalysts. We precisely modulate the Fe-N coordination environment and electronic interaction between Pt and FeN4 sites, effectively increasing the proportion of pyridine nitrogen and metal nitrogen. This dual-nitrogen design enables strong Pt-FeN4 interfacial coupling, optimizes the adsorption strength of reaction intermediates (OH*), promotes homogeneous metal dispersion, and creates a hierarchically porous carbon framework that enhances oxygen intermediates transport and active-site exposure. As a result, the optimized 40A-PtFe-CN catalyst achieves a half-wave potential of 0.923 V and a mass activity of 0.644 A mgPt-1 for the oxygen reduction reaction (ORR), exceeding that of commercial Pt/C. Moreover, the tailored electronic structure effectively suppresses H2O2 formation and mitigates Fe demetallation, delivering superior long-term durability. When used as the cathode in a PEMFC, it attains a peak power density of 1.51 W cm-2 at 80 degrees C. This work establishes a mechanistic framework in which nitrogen coordination engineering governs metal-support electronic coupling, offering a general approach for developing atomically precise, low-Pt catalysts with integrated activity and stability.