Structural transformation of molybdenum carbide with extensive active centers for superior hydrogen evolution

Abstract

Mo2C-based materials are expected to be extraordinary electrocatalysts for hydrogen evolution reaction (HER) due to their unique Pt-like electronic structures. However, the strong interaction between Mo and H as well as the scarce active centers impede their further applications. Herein, a facile and controllable route via Zn doping is proposed to weaken the H adsorption energy of Mo and create more active centers to boost the HER kinetics. A series of hierarchical branched MoC/Mo2C catalysts with promoted HER kinetics are constructed and well controlled by Zn-doping, where the structural transformation from Mo2C to MoC give rise to the optimized electronic structure and attenuate H adsorption energy. Besides, all Zn and Mo sites in Zn-MoC/Mo2C catalyst can be activated, and thereby dramatically increase the number of active centers as well as enhance the intrinsic catalytic activity. As expected, the Zn-MoC/Mo2C catalyst exhibits extremely low overpotential and Tafel slopes with excellent durability in both alkaline and acidic solutions. This work highlights a feasible strategy for enhancing hydrogen generation by dopant induced structural transformation and might provide an avenue for low-cost, efficient, and multifunctional electrocatalysts.