Synthesis of bulk WS2 nanotube phases

The synthesis of a pure phase of very long and hollow WS2 nanotubes from short but asymmetric oxide nanoparticles is described. In this process, the oxide nanoparticles grow along their longest axis; and subsequently their outermost layer is being sulfidized, while the growing oxide tip remains uncoated as long as the nanowhisker continues to grow. Thereafter, the sulfide cup is closed and a slow diffusion controlled sulfidization of the oxide core is completed within 60–120 min.