Tailoring the Mo-N/Mo-O configuration in MoO2/Mo2N heterostructure for ampere-level current density hydrogen production

Mo-based electrocatalysts have garnered significant attention for their promising hydrogen evolution reaction (HER) efficiency, however, the strong adsorption of hydrogen poses a challenge to speedy gaseous hydrogen release. In this respect, regulating the coordination of Mo atoms is an efficient strategy to optimize the electronic configuration and accelerate the HER kinetics. Herein, MoO2/Mo2N heterostructures are prepared by a programmed in situ nitridation process. The precisely controlled Mo-N/Mo-O configuration in MoO2/Mo2N heterostructure weakens hydrogen adsorption on the Mo sites leading to HER with an ampere-level current density. The electrocatalyst delivers 1 A cm−2 at an overpotential of 335 mV in 0.5 M H2SO4. Furthermore, the electrocatalyst has excellent stability by maintaining a current density of 1 A cm−2 for 180 hours with a remarkable Faradaic efficiency of 99.8%. The results reveal a novel strategy to precisely modulate the electronic configurations of low-cost transition metal-based electrocatalysts boding well for industrial-scale hydrogen production. [Display omitted] •MoO2/Mo2N heterostructure is prepared by a programmed in situ nitridation process.•Mo-N/Mo-O configuration in MoO2/Mo2N heterostructure has been precisely controlled.•The hydrogen adsorption on Mo sites is weakened by the Mo-N/Mo-O heterointerface.•The electrocatalyst needs an overpotential of 335 mV for 1 A cm−2 in 0.5 M H2SO4.•The catalyst works stably for 180 h at 1 A cm−2 with a Faraday efficiency of 99.8%.