Activation of MoS2 Basal Planes for Hydrogen Evolution by Zinc.

Molybdenum disulfide (MoS2 ) has been widely studied as a potential earth-abundant electrocatalyst for the hydrogen-evolution reaction (HER). Defect engineering and heteroelemental doping are effective methods to enhance the catalytic activity in the HER, so exploring an efficient route to simultaneously achieve in-plane vacancy engineering and elemental doping of MoS2 is necessary. In this study, Zinc, a low-cost and moderately active metal, has been used to realize this strategy by generation of sulfur vacancies and zinc doping on MoS2 in one step. Density functional theory calculations reveal that the zinc atoms not only lower the formation energy of S vacancies, but also help to decrease ΔGH of S-vacancy sites near the Zn atoms. At an optimal zinc-reduced MoS2 (Zn@MoS2 ) example, the activated basal planes contribute to the HER activity with an overpotential of -194 mV at 10 mA cm-2 and a low Tafel slope of 78 mV/dec.