MoS₂ Moiré Superlattice for Hydrogen Evolution Reaction

Abstract

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.