Preparation and electrocatalytic hydrogen evolution performance of spherical hollow MoS2/WS2 heterostructures

A heterostructure composed of spherical hollow WS2 and petal-like MoS2 was systematically studied. The results showed that the spherical hollow structures exposed more active sites, and the construction of heterostructures triggered the synergistic effect between WS2 and MoS2 and improved the hydrogen evolution reaction (HER) performances with better electron transfer ability. More importantly, the density functional theory calculations further clarified the synergistic mechanism, in which the MoS2/WS2 heterostructure could effectively regulate the hydrogen adsorption free energy to achieve the minimum value with a W/Mo atomic ratio of 2:25. Consequently, the optimized WMo-2/25 catalyst exhibited superior electrocatalytic HER activity with a low Tafel slope of 53 mV/dec as well as good durability.