Amorphous carbon supported MoS2 nanosheets as effective catalysts for electrocatalytic hydrogen evolution

Abstract

Amorphous carbon supported MoS₂, which was elaborately prepared by using a facile hydrothermal method followed by annealing, is first employed as a catalyst for the hydrogen evolution reaction (HER). Herein, we demonstrate a preparation strategy, by which MoS₂ and carbon materials could be formed in situ and simultaneously. The MoS₂ nanosheets are vertically formed on the carbon nanosphere, as illustrated in the scanning electron micrograph. The unique morphology can expose abundant edges of the MoS₂ layer as active sites for the HER, while the underlying amorphous carbon effectively improves the conductivity. By means of employing amorphous carbon as a substrate, an optimized catalyst was developed, which exhibited enhanced catalytic activity for the electrocatalytic HER with an onset potential as low as 80 mV, extremely large cathodic current density and excellent stability. Notably, a Tafel slope of 40 mV per decade was measured, which exceeds by far the activity of previous MoS₂ catalysts and suggests the Volmer–Heyrovsky-mechanism for the MoS₂-catalyzed HER.