Pt/α-MoC Catalyst Boosting pH-Universal Hydrogen Evolution Reaction at High Current Densities

Constructing subnanometric electrocatalysts is an efficient method to synergistically accelerate H2O dissociation and H+ reduction for pH-universal hydrogen evolution reaction (HER) for industrial water electrolysis to produce green hydrogen. Here, we construct a subnanometric Pt/alpha-MoC catalyst, where the alpha-MoC component can dissociate water effectively, with the rapid proton release kinetics of Pt species on Pt/alpha-MoC to obtain a good HER performance at high current densities in all-pH electrolytes. Quasi-in situ X-ray photoelectron spectroscopy analyses and density functional theory calculations confirm the highly efficient water dissociation capability of alpha-MoC and the thermodynamically favorable desorption process of hydrolytically dissociated protons on Pt sites at the high current density. Consequently, Pt/alpha-MoC requires only a low overpotential of 125 mV to achieve a current density of 1000 mA cm-2. Moreover, a Pt/alpha-MoC-based proton exchange membrane water electrolysis device exhibits a low cell voltage (1.65 V) and promising stability over 300 h with no performance degradation at an industrial-level current density of 1 A cm-2. Notably, even at a current of 100 A, the cell voltage remains low at 2.15 V, demonstrating Pt/alpha-MoC's promising potential as a scalable alternative for industrial hydrogen production. These findings elucidate the synergistic mechanism of alpha-MoC and atomically dispersed Pt in promoting efficient HER, offering valuable guidance for the design of electrocatalysts in high current density hydrogen.