One-Pot, Facile, and Versatile Synthesis of Monolayer MoS_2/WS_2 Quantum Dots as Bioimaging Probes and Efficient Electrocatalysts for Hydrogen Evolution Reaction

摘要

In this work, uniform molybdenum disulfide (MoS_2)/tungsten disulfide (WS_2) quantum dots are synthesized by the combination of sonication and solvo-thermal treatment of bulk MoS_2/WS_2 at a mild temperature. The resulting products possess monolayer thickness with an average size about 3 nm. The highly exfoliated and defect-rich structure renders these quantum dots plentiful active sites for the catalysis of hydrogen evolution reaction (HER). The MoS_2 quantum dots exhibit a small HER overpotential of ≈120 mV and long-term durability. Moreover, the strong fluorescence, good cell permeability, and low cytotoxicity make them promising and biocompatible probes for in vitro imaging. In addition, this work may provide an alternative facile approach to synthesize the quantum dots of transition metal dichalcogenides or other layered materials on a large scale.