A facile preparation of WS2 nanosheets as a highly effective HER catalyst

Tungsten disulfide (WS2) has been considered as a promising hydrogen evolution reaction (HER) candidate due to its high activity, robust chemical stability, and earth-abundant resources. However, the inert basal planes and low electrical conductivity greatly hinder its development in HER. Increasingly, the density of active sites through the structural designing is one of the most effective strategies to enhance the HER performance. Herein, we report a facile one-step hydrothermal method for synthesizing flower-like WS2 nanosheets for highly efficient HER. Besides, the effect of preparation temperature is also been discussed. The optimized WS2 nanosheets exhibit the enhanced HER activity in strong acidic solutions with a low Tafel slope and a good stability. The improvement of the HER performance can be attributed to sheet-like nanostructures, which greatly increase the edge sites and defects, resulting in a high density of exposed active sites. Besides, these sheet-like nanostructures also can make the acidic electrolyte easily accessible to the surface of WS2 and accelerate the electron transfer rate.