One-pot nanocasting of 3D ordered bicontinuous mesoporous Pt-based multimetallic alloys for efficient hydrogen evolution

The synthesis of ordered mesoporous multimetallic alloys (MMAs) with controlled composition remains challenging due to disparate reduction kinetics of multimetal precursors. Here we report a one-pot nanocasting approach in which PtFeCoNiCu salts are co-infiltrated and co-reduced within a gyroidal KIT-6 mesoporous silica scaffold, followed by template removal and acid etching, yielding single phase fcc mesoporous alloys with a 3D bicontinuous network morphology. By tuning the reduction conditions, we regulate the incorporation of Fe, Co and Ni around a PtCu-rich solid-solution lattice and remove FeCoNi overgrowths, exposing an ordered Pt-based mesoporous framework with excellent HER performance. The optimized ordered MMA catalyst, delivers an overpotential of 25 mV at 10 mA cm−2, a Tafel slope of 49.1 mV dec−1, and negligible degradation over 100 000 cycles, outperforming both commercial Pt/C and mesoporous Pt controls. This work demonstrates a general route to compositionally tuned ordered mesoporous multimetallic solid-solution alloys suitable for catalysis, sensing and related functional materials.