Nickel-doped two-dimensional molybdenum disulfide for electrochemical hydrogen evolution reaction

Ni-doped MoS 2 was developed by facile solvothermal route. Ni 2 x Mo 1− x S 2 with x = 0.05 emerged as a superior electrocatalyst with a current density value of − 405 mA cm −2 at an overpotential of − 200 mV vs. RHE. The catalyst efficiency index namely η 10 was obtained to be − 133, − 68, − 70, − 80 and − 128 mV for x = 0, 0.05, 0.1, 0.15 and 0.2, respectively. This value indicates that at lower overpotential three compositions ( x = 0.05, 0.1, 0.15) was equally efficient but with increase in overpotential x = 0.05 in Ni 2 x Mo 1− x S 2 , outstand the rest. The turn over frequency (H 2 /s) at η = − 100 mV vs. RHE for Ni 2 x Mo 1− x S 2 with x = 0, 0.05, 0.1, 0.15 and 0.2 were calculated to be 0.3, 3.5, 2.0, 1.1 and 0.6, respectively. The prime reason for the enhanced performance is attributed to the increase in the number of active sites and electronic modulation due to the synergistic effect of MoS 2 , NiS and Ni 3 S 4 . Graphic abstract