Morphology Regulation of MoS₂ Nanosheet-Based Domain Boundaries for the Hydrogen Evolution Reaction

The edge of the 2H-MoS2 phase has good electrocatalytic behavior for hydrogen evolution reaction (HER). However, the shape of monolayer MoS2 synthesized under thermodynamic equilibrium conditions is triangular, which limits the density of catalytic sites at the edge of a crystal domain. The morphology of the edge of monolayer MoS2 grown under non-thermodynamic equilibrium conditions will show a large number of dendrite nanostructures. The abundant dendrite edge nanostructures make it have more catalytic site densities than monolayer MoS2 synthesized under thermodynamic equilibrium conditions. The relationship between MoO3 source supply and MoS2 fractal dimension was established through the simulation of fractal dimension. HER performance showed that the Tafel slope (59 mV/Dec) of dendrite monolayer MoS2 was much lower than that of the triangular sample (97 mV/Dec), which confirmed that the dendrite MoS2 monolayer was more conducive to the application of hydrogen evolution reaction.