Shape controllable MoS 2 nanocrystals prepared by the single precursor route for electrocatalytic hydrogen evolution.

MoS 2 has attracted great attention as a prospective electrocatalyst for generating hydrogen via water electrolysis due to its abundant and inexpensive sources. However, bulk MoS 2 has weak electrocatalytic activity because of its low electrical conductivity and few edge-active sites. Controllable synthesis of MoS 2 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 MoS 2 with various morphologies, including quantum dots, nanorods, nanoribbons, and nanosheets. In-depth studies show that the formation of MoS 2 with various shapes is determined by both kinetic and thermodynamic factors such as reaction time and temperature. Electrocatalytic tests reveal that MoS 2 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.