Vanadium doped 1T MoS2 nanosheets for highly efficient electrocatalytic hydrogen evolution in both acidic and alkaline solutions.

• Direct growth of transition metal doped 1T-MoS 2 nanosheets on carbon paper. • Successfully reducing work function by bandgap engineering via doping. • Close-to-zero Gibbs free energy of hydrogen binding induced by vanadium doping. • Outstanding HER performance in both acidic and alkaline solutions. Electrocatalysis plays a major role in the development of clean and sustainable energies. For efficient hydrogen evolution reaction (HER) in water splitting, active, robust, and cost-effective catalysts are highly desired. Here, we present a facile approach to fabricate 1T-phase dominant V-doped MoS 2 nanosheets which can be easily grown on carbon paper at a large scale. The 5 at.% V-doped MoS 2 nanosheets achieve excellent catalytic performance, showing more than 10-fold increase of current density compared with 2H MoS 2 and a surprisingly low onset potential of 102 mV vs reversible hydrogen electrode (RHE). Moreover, it exhibits good catalytical stability in both acidic and alkaline solutions. The remarkable HER performance mainly attributes to the synergistic effects of the modified structure of MoS 2 with enhanced active sites, increased electrical conductivity, optimised energy level and near-zero Gibbs free energy of hydrogen binding. This work may shed light on achieving highly efficient electrocatalysts toward practical applications. [ABSTRACT FROM AUTHOR]