Abstract: Using petroleum residue as a precursor, this study synthesized a π-electron-rich nitrogen-doped porous carbon (NPPC) support to anchor PtCoNiFeCu high-entropy intermetallics (HEI) for the oxygen reduction reaction (ORR). Benefiting from the strong d-π interaction between NPPC and Pt, coupled with the physical confinement effect of the support, the average nanoparticle size was precisely restricted to 2.30 nm, maximizing the exposure of active sites. Concurrently, this interaction induces a significant compressive lattice strain (2.3%) within the alloy structure, optimizing the metal d-orbital charge distribution and tuning the adsorption energies of oxygen intermediates, which significantly enhances the ORR performance.Experimental results demonstrate that the as-prepared PtFeCoNiCu HEI/NPPC catalyst delivers a superior mass activity (MA) of 2.07 A mgPt-1, approximately 14-fold higher than that of commercial Pt/C. Remarkably, the catalyst retains 87% of its initial MA after 30k accelerated durability test (ADT) cycles. Furthermore, the catalyst achieves a peak power density of 1.03 W cm-2 in H2-air proton exchange membrane fuel cells (PEMFCs) at a low cathodic Pt loading of 0.1 mg cm-2, with a power loss of only 10% after 30k cycles.This work provides a simple and effective strategy for the development of highly active and durable catalysts for PEMFCs through strategic support engineering.

Key words: Porous carbon support; Lattice strain, High-entropy intermetallic compounds, Proton exchange membrane fuel cells