EXAFS Studies on the Formation of MoS2 Nanoparticles

Molybdenum sulfides were synthesized by using a ligand stabilization method with trioctylphosphine oxide (TOPO) as a coordinating solvent and molybdenum hexacarbonyl (Mo(CO)(6)) as a molybdenum precursor. In order to better understand the effect of the synthesis conditions on the morphologies of molybdenum sulfides, we varied the nucleation and the sulfidation temperature. The ligand stabilization method gave rise to the formation of oil-soluble and uniform-sized nanoparticles with spherical or slab-type structures of less than 10 nm in size. The morphology was found to highly depend on the synthesis temperature. In particular, the structural properties characterized by using X-ray absorption spectroscopy (XAS) and transmission electron microscopy (TEM) have shown that the sulfidation step at 345 degrees C induced well-developed MoS2-type structures with several levels of stacking features.