Gas Dynamically Confined Synthesis of Platinum-Based Intermetallic Nanowires for Active and Ultrastable Oxygen Reduction Catalysis

Precisely controlling the surface and internal atomic structures of platinum (Pt)-based nanocrystals remains a critical challenge for developing high-performance oxygen reduction reaction (ORR) catalysts. Here, we report a gas dynamically confined strategy leveraging hydrogen adsorption to synthesize Pt-based intermetallic nanowires (NWs) with ordered bulk atomic lattices (Pt 3 Fe L1 2, Pt 3 Co L1 2, PtNi L1 0 ) and abundant high-index {311}, {211}, and {221} facets. Dynamic hydrogen adsorption reduces surface energy and suppresses atomic migration during high-temperature annealing, preserving the one-dimensional morphology and enabling structural ordering, as confirmed by in situ transmission electron microscopy and density functional theory calculations. The resultant ordered Pt 3 Fe NWs exhibit a mass activity of 0.98 A mg Pt –1 and ultrahigh stability, retaining 93.9% of mass activity after 30,000 cycles and 86.4% of power density after 70,000 cycles. The synergistic effects of ordered atomic arrangements, high-index facets, and one-dimensional geometry optimize electronic properties and active-site energetics, enhancing both activity and stability. This strategy of designing structurally precise Pt-based intermetallic catalysts demonstrates a potential for application in fuel cell technologies.