2D Transition Metal Chalcogenide Electrocatalysts

Two-dimensional transition metal chalcogenides (2D TMCs) have recently received great attention for electronic and catalytic applications. Here we report on organic solvothermal synthesis of 2D TMCs and their electrocatalytic applications for the hydrogen evolution reaction (HER). By thermal decomposition of molybdenum carbonyl and subsequent sulfurization with element sulfur, monolayer MoS₂ nanosheets obtained via preferential in-plane growth/attachment. A mild-temperature thermal treatment was developed to remove the organic ligands without changing the chemical composition or damaging the 2D nanostructure. Further high-temperature annealing was shown to induce stacking of the MoS₂ sheets but not inducing phase transition and lateral aggregation. The 2D MoS₂ produced by our approach are highly active for the HER, with the activity found to be further dependent on stacking of the nanosheets.