Wafer-Scale Sulfur Vacancy-Rich Monolayer MoS₂ for Massive Hydrogen Production

As one of the promising low-cost and high-efficiency catalysts for the electrochemical hydrogen evolution reaction (HER), it is well-known that there are both tiny exposed catalytic active edge sites and large-area inert basal planes in two-dimensional MoS₂ structures. For enhancing its HER activity, extensive work has been done to activate the inert basal plane of MoS₂. In this article, wafer-scale (2 in.) continuous monolayer MoS₂ films with substantial in situ generated sulfur vacancies are fabricated by employing the laser molecular beam epitaxy process benefitting from ultrahigh vacuum growth condition and high substrate temperature. The intrinsic sulfur vacancies throughout the wafer-scale basal plane present an ideal electrocatalytic platform for massive hydrogen production. The fabricated vacancy-rich monolayer MoS₂ can achieve a current density of -10 mA/cm² at an overpotential of -256 mV. The wafer-scale fabrications of sulfur vacancy-rich monolayer MoS₂ provide great leaps forward in the practical application of MoS₂ for massive hydrogen production.