Sprout-like Growth of Mesoporous Mo₂C/NC Nanonetworks as Efficient Electrocatalysts for Hydrogen Evolution

Owing to their high surface areas, porous networks, nanosized walls, and unique electronic structure, mesoporous metal carbides with tailored nanoarchitectures are of particular interest for their prominent potential applications in various fields, including energy storage, fuel cells, and catalysis. Herein, we report a sprout-like growth strategy for the preparation of a mesoporous β-Mo₂C nanonetwork embedded in a nitrogen-rich carbon matrix. The nanoarchitecture can be tailored from a mesoporous Mo₂C nanonetwork film into Mo₂C nanoparticles embedded into the carbon layer. The as-prepared β-Mo₂C material was demonstrated to drive a current density of 10 mA cm⁻² at a low overpotential of 140 mV for the hydrogen evolution reaction (HER) in acidic conditions and to remain stable for at least 120 h. The excellent electrocatalytic performance may be from (1) mesoporous Mo₂C frameworks offering numerous accessible active sites; (2) a carbon layer that protects the Mo₂C from accumulation and favors electron transportation; and (3) shortened diffusion paths and ultrafine crystallinity that benefit its catalytic performance.