Synthesis, Characterization And Study On Photocatalytic Property For Molybdenum-based Nanomaterials

In this thesis, the synthesis and properties of molybdenum trioxide as well as its complex and bismuth molybdate were investigated. Hexagonal and orthorhombic phase MoO3 have been successfully fabricated by low temperature liquid reaction process; molybdenum trioxide with compound modification were prepared by chemical aging method. Moreover, bismuth molybdate were prepared by hydrothermal method. The properties of as-synthessized products were studied. On this basis, their photocatalytic decolorization and photochromic properties were investigated.The details are summarized as follows:1. Synthesis and photocatalytic properties of Molybdenum oxideHexagonal and orthorhombic phase MoO3 have been successfully fabricated by low temperature liquid reaction process. By a simple and feasible hydrothermal method, molybdenum dioxide nanoparticles were synthesized. The products were characterized by XRD, FT-IR, SEM, etc. The band gap of MoO3 was measured by UV-Vis spectrum. It was found that the band gap energy of hexagonal phase MoO3 is smaller than that of orthorhombic phase MoO3. The photocatalytic activity was evaluated by monitoring the degradation of methylene blue. It was reseached that the differences of photocatalytic degradation of methylene blue between two different phases of molybdenum trioxide.2. Preparation and properties of WO3/MoO3 complexIn order to improve the property of MoO3, we synthesized MoO3 powder doped with WO3 by the chemical ageing method. The products were characterized via X-ray powder diffraction(XRD), X-ray photoelectron spectroscopy(XPS) analysis, UV-Vis diffused reflectance spectrum(DRS) and photoluminescence(PL) spectrum. Photocatalytic activities and photochromic properties of the WO3/MoO3 products were studied. It was found that the decoloration rate of crystal violet solution with the 5% WO3/MoO3 sample was 89.12%, and the removal rate of chemical oxygen demand (COD) was 87.2%. Moreover, the oxidability of as-synthesized products enhanced with the increasing of the doped WO3. The photochromic property is improved owing to creating lots of HxW03 and HxMoO33. Hydrothermal synthesis and photocatalytic properties of bismuth molybdateTwo morphologies ofγ-bismuth molybdate(γ-Bi2MoO6) have been successfully fabricated via simply hydrothermal method. According to the of SEM, the morphologies of the as-synthesized products were octahedron and flake-like, and the formation mechanism was proposed. Ultraviolet and visible light spectrometer(UV-vis) was employed to estimate the band gap energy ofγ-Bi2MoO6. Photocatalytic activity ofγ-Bi2MoO6 was examined by monitoring the degradation of RhodamineB in an aqueous solution under solar light radiation. The result indicated that photocatalytic activity of octahedralγ-Bi2MoO6 was superior to flake-like product. We deduced that it was attributed to the difference of photoluminescence properties.