meta -Position synergistic effect induced by Ni-Mo co-doped WSe 2 to enhance the hydrogen evolution reaction.

Transition metal dichalcogenides have been the most attractive two-dimensional layered materials for electrocatalytic hydrogen evolution due to their unique structure and multi-phase electronic states. However, the enhancement of the WSe ₂ electrocatalytic hydrogen evolution reaction (HER) performance by bimetal co-doping has been rarely reported. Herein, the NiMo-WSe ₂ catalyst has been synthesized by a one-step hydrothermal reaction, with lower overpotentials of 177 and 188 mV at a current density of 10 mA cm ^-2 in 0.5 M H ₂ SO ₄ and 1 M KOH, respectively. The large specific surface area and thinner edge morphology provide more active sites for hydrogen production, thereby significantly improving the charge transfer kinetics. Density functional theory calculation results show that under acidic conditions the Δ G _H* values of NiMo-WSe ₂ with different structures and hydrogen adsorption sites are also different, when the hydrogen adsorption site was located at the top of the Se-Ni bond, the meta NiMo-WSe ₂ has a Δ G _H* value (-0.04 eV) that is closest to 0. Meanwhile, NiMo-WSe ₂ ( meta ) also has a minimum of Δ G _H* under alkaline conditions. DOS confirmed that Ni doping has a large impact on the electronic states at the WSe ₂ Fermi level, while NiMo co-doping greatly reduces the potential energy barrier of the HER reaction, jointly increasing the current density, and thus improving the HER performance.