title: New high-temperature Pb-catalyzed synthesis of inorganic nanotubes.
abstract: A new procedure for the synthesis of MoS(2) nanotubes is reported, and additionally demonstrated for MoSe(2), WS(2), and WSe(2). Highly concentrated sunlight creates continuous high temperatures, strong temperature gradients, and extended hot annealing regions, which, together with a metallic (Pb) catalyst, are conducive to the formation of different inorganic nanotubes. Structural characterization (including atomic resolution images) reveals a three-step reaction mechanism. In the first step, MoS(2) platelets react with water-air residues, decompose by intense solar irradiation, and are converted to molybdenum oxide. Subsequently, the hot annealing environment leads to the growth of Pb-stabilized MoO(3-x) nanowhiskers. Shortly afterward, the surface of the MoO(3-x) starts to react with the sulfur vapor supplied by the decomposition of nearby MoS(2) platelets and becomes enveloped by MoS(2) layers. Finally, the molybdenum oxide core is gradually transformed into MoS(2) nanotubes. These findings augur well for similar syntheses of as yet unattained nanotubes from other metal chalcogenides.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100, Israel.
authors.forename: Olga
authors.initials: O
authors.lastname: Brontvein
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Stroppa
authors.forename: Ronit
authors.initials: R
authors.lastname: Popovitz-Biro
authors.forename: Ana
authors.initials: A
authors.lastname: Albu-Yaron
authors.forename: Moshe
authors.initials: M
authors.lastname: Levy
authors.forename: Daniel
authors.initials: D
authors.lastname: Feuerman
authors.forename: Lothar
authors.initials: L
authors.lastname: Houben
authors.forename: Reshef
authors.initials: R
authors.lastname: Tenne
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gordon