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

MoS has attracted great attention as a prospective electrocatalyst for generating hydrogen water electrolysis due to its abundant and inexpensive sources. However, bulk MoS has weak electrocatalytic activity because of its low electrical conductivity and few edge-active sites. Controllable synthesis of MoS 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 with various morphologies, including quantum dots, nanorods, nanoribbons, and nanosheets. In-depth studies show that the formation of MoS with various shapes is determined by both kinetic and thermodynamic factors such as reaction time and temperature. Electrocatalytic tests reveal that MoS quantum dots have high electrocatalytic performance with a low overpotential of 255 mV and a small Tafel slope of 66 mV dec due to the abundant exposed active edges and excellent intrinsic conductivity.