Salt Matrix Strategy for General Synthesis of High-Loading Intermetallic Pt₃M Catalysts toward Electrocatalytic Hydrogen Evolution

Pt-based intermetallics are considered a promising class of electrocatalysts owing to their outstanding activity and stability. However, the synthesis of intermetallics usually requires high-temperature annealing, and it is difficult to prepare small-sized and uniformly dispersed intermetallics. Herein, a practicable and affordable salt matrix strategy is proposed for the controlled synthesis of ordered L1₂-/L1₀-type Pt-M (M = Fe, Co, Mn, and Cr) intermetallics. BaCl₂ acts as a salt matrix, trapping nanoparticles to avoid particle sintering and controlling nanoparticle agglomeration during high-temperature annealing, even at high load (50 wt %). Moreover, BaCl₂ has the advantage of being easily removed from the final product. In the instance of preparing ordered intermetallic Pt₃Fe, high hydrogen evolution activity (mass activity 2.44 A mg_Pt^-1) and excellent stability are presented in the membrane electrode assembly (only 0.6% attenuation after chronopotentiometry). The salt matrix strategy, which explores an economical and scalable approach to the controlled synthesis of Pt-based intermetallics, paves a way for the commercialization of PEM water electrolysis technology.