The sluggish kinetics and limited durability of the oxygen reduction reaction (ORR) at the cathode remain a major barrier to thewidespread deployment of proton exchange membrane fuel cells (PEMFCs). Here, we introduce a low-temperature interfacialengineering strategy to construct ternary L1 2 -ordered Pt 3 (Co,Mn) 1 intermetallic nanoparticles. A conformal MnO shell on Pt 3 Co1cores not only suppresses particle coalescence but also undergoes redox activation to generate interfacial oxygen vacanciesthat initiate the disorder-to-order transition. During thermal activation, these vacancies mediate Co–Mn atomic exchangeacross the core@shell interface, forming interfacial Co–O and intralattice Pt–Mn bonds that cooperatively stabilize the orderedframework. This oxygen-vacancy-driven interfacial evolution reconfigures the Pt electronic structure, downshifting the d-bandcenter, enriching electron density at Pt active sites, and optimizing oxygen-intermediate adsorption. The resulting catalyst exhibitshigh intrinsic ORR activity and outstanding durability over extended accelerated cycling. When implemented into practicalmembrane-electrode assemblies, it surpasses the U.S. Department of Energy (DOE) 2025 PEMFC benchmarks for both rated powerdensity and durability, demonstrating its promise for real-world fuel cell applications. More broadly, this work establishes redox-active, confinement-mediated interfacial engineering as a general paradigm for directing atomic ordering and electronic structurein complex multimetallic electrocatalysts.
DOI 링크: https://doi.org/10.1002/adma.202521036