Unlocking Low-Temperature Ordering of Supported Pt-Based Intermetallic Compounds via Binary Salt-Matrix Strategy

Structurally ordered Pt-based intermetallic compounds (IMCs) are crucial for developing high-performance fuel cells but remain notoriously difficult to synthesize at low temperature due to the formidable kinetic barriers of solid-state atomic diffusion. Herein, we overcome this long-standing challenge via a binary salt matrix (KCl-Na₂HPO₄) strategy that drives disorder-to-order phase transition of carbon-supported Pt₃Co catalysts. Mechanistic studies suggest that in-situ generated Na₄P₂O₇ in binary salt matrix contributes to the partial removal of surface CoO, thereby weakening the surface oxide constraint and creating favorable conditions for the subsequent ordering process. Meanwhile, the binary salt matrix provides a flexible confinement environment that limits excessive nanoparticle growth and is proposed to facilitate atomic rearrangement during the disorder-to-order transition. The resulting catalyst, featuring an ordered Pt₃Co core and Pt shell, exhibits a peak power density of 1.4 W cm^-2 in H₂/air single cell and maintained 85% of its peak power density after 30 000 cycles of accelerated durability tests (ADT), outperforming disordered Pt₃Co catalyst. This work provides an innovative strategy for the large-scale direct preparation of carbon support Pt-based intermetallic compounds at low temperature, providing great significance for promoting the development of advanced catalysts.