Ambient Synthesis of Pt-Reactive Metal Alloy and High-Entropy Alloy Nanocatalysts Utilizing Hydrogen Cold Plasma

Synthesis of platinum-reactive metal alloy (Pt-RMA) and its high-entropy alloy (Pt-HEA) nanoparticles is challenging due to the huge difference in reduction potentials between Pt and reactive metal precursors and the oxyphilic nature of reactive metals. Herein, we utilize hydrogen cold plasma to synthesize a variety of Pt-RMA (Pt–Cr, Pt–Ta, Pt–V, Pt–Fe, and Pt–Al) and Pt-HEA (Pt–Cr–Ta–V–Fe–Al) nanoparticles under ambient conditions. Effectiveness of the method is attributed to the generation of hydrogen anions in hydrogen plasma, possessing extremely strong reducing ability with its −2.3 V standard reduction potential that can simultaneously reduce Pt and reactive metal precursors. The synthesized nanoparticles are characterized for confirming the alloy formation and are studied for the catalytic properties in the methanol oxidation reaction, with improved activity and durability compared to commercial Pt. This study provides an effective, universal method to synthesize Pt-RMA and Pt-HEA nanoparticles, which offers a new platform for studying this group of nanomaterials.