Shape controllable MoS₂ nanocrystals prepared by the single precursor route for electrocatalytic hydrogen evolution

MoS₂ has attracted great attention as a prospective electrocatalyst for generating hydrogen via water electrolysis due to its abundant and inexpensive sources. However, bulk MoS₂ has weak electrocatalytic activity because of its low electrical conductivity and few edge-active sites. Controllable synthesis of MoS₂ with ultrasmall size or complex morphology may be an available strategy to boost its conductivity and edge-active sites. Herein, a facile single-precursor strategy was developed to prepare nanoscale MoS₂ with various morphologies, including quantum dots, nanorods, nanoribbons, and nanosheets. In-depth studies show that the formation of MoS₂ with various shapes is determined by both kinetic and thermodynamic factors such as reaction time and temperature. Electrocatalytic tests reveal that MoS₂ quantum dots have high electrocatalytic performance with a low overpotential of 255 mV and a small Tafel slope of 66 mV dec^-1 due to the abundant exposed active edges and excellent intrinsic conductivity.