Platinum-based high-entropy alloys for electrocatalysis: preparation, applications and prospects.

Platinum-based high-entropy alloys (Pt-HEAs), composed of multiple principal elements in near-equiatomic ratios, have emerged as a transformative class of electrocatalysts that overcome the long-standing activity-stability-cost trade-off associated with conventional Pt catalysts. The unique high-entropy effect, severe lattice distortion, sluggish atomic diffusion, and synergistic multi-metal interactions endow Pt-HEAs with tunable electronic structures, abundant heterogeneous active sites, and exceptional resistance to corrosion and sintering. This review systematically summarizes recent advances in the rational design, synthesis, and electrocatalytic applications of Pt-HEAs. We first outline the thermodynamic and kinetic fundamentals governing entropy-stabilized solid-solution formation, followed by a comprehensive comparison of state-of-the-art synthetic strategies, including electrodeposition, laser-based manufacturing, carbothermal shock, high-temperature liquid shock, spray-drying-assisted reduction, Joule heating, and microwave-assisted processes. We then discuss the electrocatalytic behavior of Pt-HEAs in key reactions including hydrogen evolution reactions, oxygen evolution reactions, hydrogen oxidation reactions, and oxygen reduction reactions. Particular emphasis is placed on mechanistic insights revealed by advanced in situ/operando characterization and density functional theory calculation. Finally, we propose the remaining challenges and future opportunities in composition design, precise structural control, entropy-defect coupling, machine-learning-assisted discovery, and industrial-scale catalyst integration. This review aims to provide a mechanistic framework and design principles for advancing Pt-HEAs toward next-generation, high-performance, and durable electrocatalysts for clean-energy conversion technologies.