Heteronanowires of MoC–Mo₂C as efficient electrocatalysts for hydrogen evolution reaction

Exploring efficient noble-metal free electrocatalysts for the hydrogen evolution reaction (HER) is one of the most promising pathways for facing the energy crisis. Herein, MoC-Mo₂C heteronanowires composed of well-defined nanoparticles were accomplished <i>via</i> controlled carbonization, showing excellent HER activity, fast kinetic metrics and outstanding stability in both acid and basic electrolytes. In particular, the optimal one consisting of 31.4 wt% MoC displayed a low overpotential (<i>η</i>₁₀ = 126 and 120 mV for reaching a current density of -10 mA cm^-2), a small Tafel slope (43 and 42 mV dec^-1) and a low onset overpotential (38 and 33 mV) in 0.5 M H₂SO₄ and 1.0 M KOH, respectively. Such prominent performance, outperforming most of the current noble-metal free electrocatalysts, was ascribed to the carbide surface with an optimized electron density, and the consequently facilitated HER kinetics. This work elucidates a feasible way toward efficient electrocatalysts <i>via</i> heteronanostructure engineering, shedding some light on the exploration and optimization of catalysts in energy chemistry.