Direct sulfidization synthesis of high-quality binary sulfides (WS2, MoS2, and V5S8) from the respective oxides

High-quality binary sulfides WS2, MoS2, and V5S8 have been prepared via a direct sulfidization route from the respective oxides, using NH3-H2O and CS2 as starting materials to produce H2S acting as sulfur source. Characterizations by X-ray powder diffraction and X-ray photoelectron spectra suggest that all three sulfides have the pure phases and stoichiometric compositions as expected. Flaky WS2 and V5S8 with irregular shapes are determined by transmission electron microscopy. In particular, MoS2 submicrometer spheres with the yield of ca. 100% are observed by field-emission scanning electron microscopy. It is found that the reaction temperature plays an important role in the reaction system. A possible mechanism is proposed. (C) 2004 Elsevier B.V. All rights reserved.