Synergistic W and V Doping Induce Defects and Thus a High Catalytic Surface Area in MoS ₂ for the Hydrogen Evolution Reaction

Owing to its large earth crust abundance, long‐term stability, and high intrinsic conductivity, molybdenum sulfide (MoS ₂ ) has emerged as a promising hydrogen evolution reaction (HER) electrocatalyst. However, the key challenge for the HER is to activate the broader inert basal plane of MoS ₂ to increase the density of active sites and maximize catalytic activity. Heteroatom doping can open sulfur vacancies and produce defects that create additional active sites. Herein, we demonstrate for the first time a trimetallic W‐ and V‐doped MoS ₂ nanocatalyst synthesized with different doping ratios by a green synthesis route. W and V dopants induce a synergistic effect on the nanoflower‐shaped MoS ₂ structure, increasing the density of defects in the MoS ₂ 2D layer as well as in layer stacking. We show a correlation between defect density, increased number of exposed edge sites, enhanced active surface area, and better electrocatalytic activity in this series of materials. The best W and V codoped MoS ₂ electrocatalyst exhibits an overpotential of 186 mV at 10 mA·cm ⁻² for HER, which is 1.2 times lower than that of pristine MoS ₂ , and delivers hydrogen production with 100% Faradaic efficiency in continuous operation for over 16 h.