Lawrence Berkeley National Laboratory

Transition metal dichalcogenides (TMDs, such as MoS2, WS2 and MoSe2) with lamellar structures have attracted tremendous attention owing to their similar structure to graphite. However, two-dimensional (2D) TMD nanomaterials display a strong tendency to restack and condense, which leads to a marked decrease of performance in their applications. In this study, we report the synthesis of TMDs by using polyoxometalates (POMs) as tungsten or molybdenum precursors. Hierarchical TMDs with novel structures can be formed below 200 °C, including WS2 rods, MoS2 rods and MoSe2 hollow spheres. All of these structures assembled from the corresponding nanosheets. Meanwhile the epitaxial growth of noble metal nanoparticles (NPs) on TMDs could be achieved very easily. The obtained Pt/WS2 and Pt/MoS2 hybrids were highly active and durable HER catalysts. In addition, the Pt NPs on the surface of TMDs could improve the HER activity sharply, which was likely due to the synergistic effect between Pt NPs and MoS2 rods.