Radial hierarchical carbon spheres for Pt‐efficient oxygen and hydrogen catalysis in anion exchange membrane fuel cells

Efficient oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) bifunctional catalysts are essential for anion exchange membrane fuel cells (AEMFCs), but the high cost and limited durability of Pt‐based catalysts remain major barriers to practical implementation. Herein, we report an ethanol‐mediated interfacial co‐assembly strategy to synthesize hollow carbon spheres (CS) with a center‐symmetric radial hierarchical architecture. This open porous framework provides spatial confinement and abundant anchoring sites for highly dispersed Pt nanoparticles, while the radial channels facilitate mass transport and improve active‐site accessibility. The optimized Pt/CS‐71 catalyst delivers excellent ORR and HOR activity in alkaline electrolyte. Finite element simulations further indicate that radial channels act as efficient mass‐transport pathways, reducing diffusion resistance and promoting reactant penetration throughout the hollow carbon framework. When applied in AEMFCs, Pt/CS‐71 enables a peak power density of 1.15 W cm −2 and a mass power density of 7.92 W mg PGM −1 , together with stable long‐term operation.