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 Fesingle bondN 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 °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.