Hydrogen evolution reaction catalyst with high catalytic activity by interplay between organic molecules and transition metal dichalcogenide monolayers

Introducing sulfur vacancies (S_V) in monolayer molybdenum disulfide (MoS₂) is a well-known approach to activate the inert basal planes for efficient hydrogen evolution reaction (HER). However, higher S_V induction accelerates the disruption of the crystal structure. We report an efficient method for improving catalytic activity and durability via covalent melamine (MEL) functionalization at S_V sites in the basal plane of transition metal dichalcogenide (TMD) monolayers. Functionalized 2H–MoS₂ requires only an overpotential of 160 mV at 100 mAcm⁻² in acidic medium with chronoamperometric durability of more than 14 h at 30 mAcm⁻². Our theoretical results reveal that chemical functionalization creates novel HER active sites, where catalytic activity of the MEL−MoS₂ catalyst arises from the interplay of the ring N sites of the MEL and the S atoms on the 2H–MoS₂ surface. These findings of chemically coupled organic molecule−TMD system will pave new avenues for development of superior HER catalysts.