Nanoconfined Solvothermal Synthesis of Defective 1T-MoS Monolayers with High Electrocatalytic Performance.

Synthesizing 2D nanosheets in a controlled and scalable manner remains a significant challenge. Here, a nanoconfined solvothermal synthesis is presented of metallic phase MoS (1T-MoS) monolayers at kilogram scale. The MoS nanosheets exhibit a remarkably high monolayer ratio of 97%, a 1T content of ≈89%, and a well-defined average lateral size ranging from ≈100 nm to 1.0 µm, with a narrow size distribution. Moreover, these nanosheets possesses abundant surface defects, and the defect density can be regulated in situ through changing the reaction conditions. Intriguingly, the monolayer MoS nanosheets demonstrate good dispersibility and high stability in various solvents, including water, ethylene glycol, dimethyl formamide and others, with a high concentration of up to 1.0 mg mL. They are also proven to be high-performance electrocatalysts for the hydrogen evolution reaction, exhibiting an overpotential of 315 mV at an industrial current density of 1000 mA cm and maintaining constant current densities of 500 mA cm for up to 100 h, surpassing the performance of the commercial 20 wt.% Pt/C. Our strategy represents a significant advancement in the controlled synthesis of monolayer MoS at scale, providing a promising avenue for the practical application of 2D materials.