One-Dimensional Metal Oxides And Sulfides Nanomaterials: Synthesis, Characterization And Their Properties

Owing to unique physical properties, nanostructured metal oxides andsulfides have exhibited promising applications in catalysis, sensing, optics,magnetics and batteries. Preparing novel 1D nanostructures and investigatingtheir general formation mechanism may be a solution to the precise control oftheir sizes, dimensionalities and properties. In this dissertation, systematicexplorations have been carried out on new synthetic strategies of metal oxidesand sulfides, their formation mechanisms and novel properties.A direct pyrolysis method from artificial lamellar mesostructures to WS₂nanotubes, W and WO₃ nanowires has been developed and MoS₂ nanotubeswere also prepared from a conversion reaction. Based on experimental facts, arolling mechanism, which provided a new viewpoint for the formation of 1Dnanostructures, has been proposed.Several gas phase reactions were established to prepare MoCO/Mo₂Cmicrotubes, MoS₂ and WS₂ nanotubes, fullerenes, nanoflowers and Temicrotubes. Systematical studies of their BET surface areas, field-emissioneffect and magnetoresistance (MR) effect indicated promising applications ofthese novel materials in catalysis, flat panel displays and MR devices.Rational hydrothermal reactions have been developed to prepare singlecrystal MoO₃ nanobelts and MoS₂ nanostructures. Nanorods and nanoflakes ofseveral metal hydroxides were prepared with a simple conversion method.Reversible intercalation of Mg²⁺ in MoS₂ nanostructure was demonstrated,suggesting the possibility of using layered nanomaterials as electrodes.WO₃ hollow spheres and highly crystallized, re-dispersible TiO₂ wereprepared by controlled non-aqueous reactions. WO₃ hollow sphere gas-sensorswere developed and the TiO₂'s photodegradation property was observed.