MoS2 AND WS2 NANOTUBES ALLOYED WITH GOLD AND SILVER

We report on the existence of MoS2 and WS2 micro- and nanotubes alloyed with gold and silver. The tubes have been grown by chemical transport reaction with iodine as a transport agent. While the undoped inorganic tubes grow by spiral rolling of the molecular layers, the presence of noble metals can partially or completely remove the chirality. The molecular layers grow in the form of coaxial cylinders. The noble metal is situated inside the walls of the tubes. It influences the longitudinal terminations of the tubes and increases the wall thickness. Distortion of every second van der Waals gap reveals that staging is present. Stop of chirality in alloyed inorganic tubes appears to be strongly coupled with the expansion of VdW gaps. The existence of MxMoS2 and MxWS2; (M: Au, Ag) ternary compounds, which are not known in the usual plane layered structures, gives evidence that the cylindrical geometry of crystals can stabilize new compounds and changes the chemistry as well as the physical properties of the materials.