A heterostructured WS2/WSe2 catalyst by heterojunction engineering towards boosting hydrogen evolution reaction

Two-dimensional (2D) heterostructure presents excellent flexibility in modifying the electrocatalytic activity. Transition metal dichalcogenides (TMDs) which have some heterostructure were used to improve the exposure of active sites, revealed an excellent catalytic activity for hydrogen evolution reaction (HER) and continue to attract many studies. In this study, we design a unique flowerlike WS2/WSe2 heterostructure by heterojunction engineering. This multiscale morphology control design combines the compositional and structural advantages of WS2/WSe2 heterojunction into a hierarchical architecture, which can modulate electronic structure, remarkably facilitating the exposure of the more electrochemical active sites. As expected, the heterostructured WS2/WSe2 catalyst displays remarkable HER property with a low overpotential of 121 mV at 10 mA cm−2, and a small Tafel slope of 74.08 mV dec-1 with significant durability. We introduce the first example of flowerlike WS2/WSe2 heterostructure as a HER electrochemical catalyst. This work is expected to open a new door for the discovery of other 2D heterostructure as effective catalysts for renewable energy.