Yeda Research and Develpment & Co. Ltd

Moshe Homyonfer

Reshef Tenne

Yishay Feldman

Aude Rothschild

Nanotubes of transition metal chalcogenides as long as 0.2-20 microns or more, perfect in shape and of high crystallinity, are synthesized from a transition metal material, e.g. the transition metal itself or a substance comprising a transition metal such as an oxide, water vapor and a HX gas or Hgas and X vapor, wherein X is S, Se or Te, by a two-step or three-step method including first producing nanoparticles of the transition metal as long as 0.3 microns, and then annealing in a mild reducing atmosphere of the aforementioned gas or gas mixture. The transition metal chalcogenide is preferably WSor WSe. Tips for scanning probe microscopy can be prepared from said long transition metal chalcogenide nanotubes.

Bulk synthesis of long nanotubes of transition metal chalcogenides

A method for the preparation of nanoparticles of metal oxides containing inserted metal particles and to metal-intercalated and/or metal-encaged &ldquo;inorganic fullerene-like&rdquo; (hereinafter IF) structures of metal chalcogenides obtained therefrom is provided, which comprises heating a metal I material with water vapor or electron beam evaporation of said metal I material with water or another suitable solvent, in the presence of a metal II salt, and recovering the metal II-doped metal I oxide, or proceeding to subsequent sulfidization, yielding bulk quantities of metal II-intercalated or metal II-encaged IF structures of the metal I chalcogenide. The metal II salt is preferably an alkaline, alkaline earth or transition metal salt, most preferably an alkali chloride. The intercalated and/or encaged IF structures are usable as lubricants. They also form stable suspensions, e.g. in alcohol, and electrophoretic deposition from said suspensions yields thin films of the intercalated IF materials, which have a range of potential applications.

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New York, NY, United States of America

Moshe Homyonfer