Modulating Electronic Structure and Mass Transfer Kinetics via Mo‐Mo₂C Heterostructure for Ampere‐Level Hydrogen Evolution

Abstract Molybdenum carbide (Mo₂C), known for its platinum‐like electronic structure and excellent corrosion resistance, has demonstrated promising catalytic performance in laboratory tests. However, under industrial harsh conditions, the catalytic performance of Mo₂C faces constraints due to its inherently strong hydrogen adsorption. Additionally, at elevated current densities, rapid depletion of active species in the electrolyte, coupled with hydrogen gas bubble accumulation, introduce significant mass transport challenges. This work introduces an electrode with Mo‐Mo₂C heterostructures supported on a Mo plate (Mo‐Mo₂C/Mo). Further analyses reveal that incorporating metallic Mo into the heterostructures optimizes the electronic structure of Mo₂C. This optimization achieves a more balanced hydrogen adsorption, while also enhancing the capacity for water adsorption and dissociation of Mo₂C, collectively improving catalytic activity. Furthermore, this electrode features a unique “bush‐like” surface morphology that can induce a “turbulence” effect in the electrolyte near the electrode surface, facilitating electrolyte flow and mass transport. As a result, the Mo‐Mo₂C/Mo electrode exhibits excellent catalytic performance at high current densities (η₁₀₀₀ = 452 mV). Moreover, the strong corrosion resistance and robust integration of Mo and Mo₂C ensure long‐term stability, with the electrode remaining stable at 1.5 A in 6 M KOH over extended periods.