Vanadium-Doped WS2 Nanosheets Grown on Carbon Cloth as a Highly Efficient Electrocatalyst for the Hydrogen Evolution Reaction.

Two-dimensional transition-metal dichalcogenides have been widely studied as electrocatalysts for the hydrogen evolution reaction (HER). However, limited active sites and poor conductivity hinder their application. To solve these disadvantages, heteroatom doping has attracted wide attention because it can not only increase the active sites but also affect the intrinsic catalytic properties of the electrocatalyst. Herein, we grew vanadium-doped WS2 nanosheets on carbon cloth (V-WS2 /CC) as an electrocatalyst for HER under acidic and alkaline conditions. With a proper vanadium doping concentration, the electrochemical surface areas of V0.065 -WS2 /CC were 9.6 and 2.6 times as large as that of pure WS2 electrocatalyst under acidic and alkaline conditions, respectively. In addition, the charge-transfer resistance also decreased with moderate vanadium doping. Based on this, the synthesized vanadium-doped WS2 nanosheets exhibited good stability with high HER catalytic activity and could reach a current density of 10 mA cm-2 at overpotentials of 148 and 134 mV in 0.5 m H2 SO4 and 1 m KOH, respectively. The corresponding Tafel slopes were 71 and 85 mV dec-1 . Therefore, our synthesized vanadium-doped WS2 nanosheets can be a promising electrocatalyst for the production of hydrogen over a wide pH range.