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Numerous efforts in improving the hydrogen evolution reaction (HER) performance of transition metal dichalcogenides mostly focus on active sites exposing, vacancy engineering, and phase engineering. However, little room is left for improvement in these approaches. It should be noted that efficient electron transfer also plays a crucial role in catalytic activity. In this work, by employment of an external vertical magnetic field, ferromagnetic bowl-like MoS 2 flakes can afford electrons transmitting easily from a glassy carbon electrode to active sites to drive HER, and thus perform magnetic HER enhancement. The ferromagnetic bowl-like MoS 2 flakes with an external vertical magnetic field can provide a roughly doubled current density compared to that without an external vertical magnetic field at a constant overpotential of −150 mV. Our work may provide a new pathway to break the bottleneck for further improvement of HER performance and also paves the way to utilize the magnetic enhancement in widely catalytic application.

A MoS2 moiré superlattice with a twisted angle of θ ≈ 7.3° via a facile method instead of a conventional mechanical stacking method is successfully fabricated. With reduced interlayer potential barriers demonstrated by first-principles calculations and ultralow frequency Raman spectra, electrons can transfer easily from a conductive substrate to active sites in this MoS2 superlattice, thus leading to good hydrogen evolution reaction (HER) activities. By using an electrochemical microcell technique, improved catalytic performance in the MoS2 moiré superlattice is validated, with a current density of −10 mA/cm2 at an overpotential of −153 mV and a Tafel slope of 73 mV/dec. A strategy to boost the electrocatalytic performance by reducing the interlayer potential barriers is successfully achieved by employing a MoS2 moiré superlattice. The work paves a new pathway to break the bottleneck for further improvement of HER performance and also opens interesting possibilities for implementing moiré superlattices in catalysis, energy storage, and 2D functional devices.

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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.