| Tungsten disulfide(WS2) is a typical layered inorganic material with strong S-Mo-S covalent bonds and weak Van der Waals force between layers. Accordingly, tungsten disulfide nanomaterials were not only used in the field of lubrication and catalysts, but also widely used in lithium batteries, hydrogen storage, photoelectricity, and so on. Much attention has been focused on Tungsten disulfide nanomaterials due to their unique physical and chemical properties and broad potential applications. Due to the structural anisotropy, the differences of morphology and structure will affect the performances significantly. Therefore, it is necessary to explore novel methods which can control the preparation of microstructures, enhancing the final performances. And then, they can be used in more fields, which is very important for developments of theory and applications.The current thesis is focused on using hydrothermal methods to prepare tungsten disulfide nanomaterials with the assistance of surfactants, discussing the formation mechanism of the products’ morphologies and structures, and exploring their potential applications. On the other hand, the thesis also explored the synthetic method of the nano-composite catalysts(WS2/Ti O2 composites,WO3/Ti O2 nano-composites, WO3/WS2 nano-composites), and studied the optical performance of the composite catalysts. This paper includes the following content:The low dimensional WS2 nanostructures of the nanospheres, nanowires, nanorods, nanosheets, and WS2 nanoflowers hierarchical structures self-assembled by nanosheets have been successfully synthesized by a facile hydrothermal method assisted with cetyl trimethyl ammonium bromide(CTAB). According to the CTAB concentration and different temperature, the micelle structures can be further accumulated to different liquid crystal structures(spherical, cylindrical, lamellar, as well as the hexahedron micelles, etc.). The micelles played an important role as a template. The as-prepared products were characterized by ultraviolet-visible spectrometer. The WS2 nanostructures have a wide absorption in the visible light region, and may have excellent catalytic activity as visible light photocatalysis.The WS2 nanofibers self-assembled by nanoparticles have been successfully synthesized by a facile hydrothermal method assisted with polyethylene glycol(PEG-20000). The polyethylene glycol played an important role as a template and the possible formation mechanism was discussed. Because of the small size and large specific surface area of the WS2 nanofibers, it had a wide absorption and high absorption strength in the visible light region. Therefore, the WS2 nanofibers may have broad application prospects as visible light photocatalysis.The flower-like WS2 nanospheres self-assembled by sheets have been successful-ly prepared by a facile hydrothermal method assisted with the sodium metasilicate. The flower-like nanospheres had uniform size of about 1 μm in diameter, and the the thickness of nanosheets was about 10-20 nm. Besides, the porous flower-like WS2 nanostructures were successfully synthesized via a facile the compound surfactants-assisted hydrothermal route. The flower-like nanostructures with an average diameter of 200nm-300 nm, was self-assembled by the porous nanosheets. The compound surfactants(CTAB-F127) played an important role. The flower-like WS2 nanostructures had large specific surface area, 49.856m2g-1 and 78.331m2g-1, respectively, and had a wide absorption in the visible light region.Nanosized WS2 and WO3 respectively sensitized titanium dioxide(Ti O2) was successfully prepared via a simple yet facile hydrothermal process. The nanoscale WS2/Ti O2 composites consisted of millions of small nanoparticles with diameters in the range of several nanometers. So the composites were loose and porous, and average diameter was about 300nm-350 nm. The WS2 nanoparticles were interlacedly distributed around Ti O2 nanoparticles. The WS2/Ti O2 composites had a wide absorption in the visible light region. The WS2 acted as sensitizers, which may make the nano-WS2/Ti O2 composites have excellent catalytic activity as visible light photocatalysis. Besides, compared with Ti O2, the adsorption edge of the nano-WO3/Ti O2 composites exhibited significant red shifts, and the absorption strength decreased obviously.The WO3/WS2 compound has successfully been prepared by reducing the precursor(WO3) with H2 S and H2 at 400℃for 2H. The precursor(WO3) have been synthesised via a low temperature hydrothermal route. the composites had average diameter was about 60nm-100 nm. The outer layer and center of the nanopartciles were WS2, WO3, respectively. The WO3/WS2 compound had a wide absorption in the UV-visible light region. The interaction between WS2 and WO3 effectively promoted the separation of photogenerated electrons and holes, which resulted in that the volume of the photogenerated electrons and holes increased, and that the lifetime of the photocarrier prolonged. Therefore, the nano-WO3/WS2 compound exhibited excellent catalytic activity as UV-visible light photocatalysis. |
PDF Full Text Request