Pt/Mo2C Nanocatalyst Prepared by Cluster Beam Deposition for Hydrogen Evolution Reaction

The practical application of the hydrogen evolution reaction (HER) in water electrolysis is severely hindered by the high cost, high Pt loading, insufficient durability, and agglomeration tendency of noble-metal nanoparticles. Despite numerous recent strategies, their overall performance remains unsatisfactory. Herein, we report a Pt/Mo 2 C composite catalyst with tunable cluster size and intimately coupled interfaces, precisely fabricated by a cluster beam deposition (CBD) strategy. The optimized catalyst delivers overpotentials of only 47 mV in acidic media and 228 mV in alkaline media at a current density of 10 mA cm –2 . Remarkably, it exhibits outstanding long-term stability (110 h) under acidic conditions, along with significantly improved Pt utilization. The catalyst achieves a high mass activity of 43.9 A mg pt –1 at an overpotential of 50 mV, outperforming many benchmark Pt-based catalysts. Comprehensive characterizations reveal pronounced interfacial electron transfer from Pt to Mo 2 C, which optimizes the d-band center of Pt and the adsorption energy of hydrogen intermediates. Furthermore, particle agglomeration and surface passivation are effectively suppressed, accelerating charge transfer and hydrogen desorption kinetics. This work presents a strategy for the rational fabrication of metal clusters with precise size control and offers a paradigm for designing noble metal/transition metal carbide hybrid electrocatalysts.