Ce ~ (3 +) / F ~ -/TiO_2 and F ~ -/SiO_2/TiO_2 photocatalytic properties of nanowires

Title: Ce ~ (3 +) / F ~ -/TiO_2 and F ~ -/SiO_2/TiO_2 photocatalytic properties of nanowires
　　Author: Wang Jianjun
　　Degree-granting units: Nanchang University
　　Keywords: titanium dioxide;; nanowires;; photocatalytic properties
　　Summary:
　　Represented by TiO2 photocatalytic technology using sunlight at room temperature, decomposition of pollutants, is a broad prospect of pollution control technology. But the TiO2 band gap (3.2eV), can only be used in the ultraviolet part of sunlight, and ultraviolet part of sunlight only 3-4%. So TiO2 photocatalyst in practice difficult to get large-scale promotion Magnetic lifter and application.
　　Through the introduction of non-metallic elements and rare earth ion doped TiO2 modified, can effectively expand the range of spectral response and increase TiO2 photocatalytic efficiency. In this study, selection of rare earth elements neodymium and cerium, and non-metallic elements nitrogen, fluorine, and silica, the sol - gel electrophoresis were prepared by a variety of different combinations of doped TiO2 nanowire photocatalyst. And methyl orange as reactants investigated various photocatalysts under UV irradiation of the catalytic performance, we can see from the experimental elements and cerium, and fluorine doped silica and fluorine co-doped photocatalyst has both excellent photocatalytic performance. By using UV - visible diffuse reflectance (Uv-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM) of TiO2 nanowires obtained were characterized and studied Ce3 + / F-/TiO2 nanowire photocatalyst and F-/SiO2/TiO2 nanowire photocatalyst photocatalytic performance. The results show that: Preparation of Ce3 + / F-/TiO2 photocatalyst for visible light absorption edge red-shifted. The average particle size of photocatalyst 4.6nm, evenly dispersed, crystalline phase of anatase and rutile coexist. Fluorine doped TiO2 in visible light can also be inspired to improve the photocatalytic performance. Cerium-doped catalyst particles are mainly to restrain growth, increased hole capture channels, reducing the photo-electron and hole recombination rate effect. The nanowires prepared F-/SiO2/TiO2 photocatalyst particle size of about 10nm, crystalline phase anatase and rutile phases coexist. Incorporation of SiO2 TiO2 crystal structure makes stable, smaller grain size and highly dispersed in the matrix. Incorporation of F ions can effectively reduce the grain size, to improve the photocatalytic efficiency.
　　Optical properties of the catalyst preparation conditions have a greater impact. The goal of this experiment reaction of methyl orange solution of Ce3 + / F-/TiO2 F/SiO2/TiO2 nanowires and nanowire photocatalyst photocatalytic calcination temperature, calcination time of preparation conditions and doping concentration were studied. The results http://www.999magnet.com/products/131-magnetic-lifter show that: Ce3 + / F-/TiO2 nanowire photocatalyst optimum preparation conditions for the cerium doped 0.4mol%, 500 ℃ calcined 2h. Photocatalytic system from 1h after the reaction of methyl orange degradation rate of 95% or more. The preparation conditions F/SiO2/TiO2 photocatalyst doped SiO2 concentration of 2mol%, 500 ℃ calcination 2.5h. The catalytic system obtained after 45min in the reaction of methyl orange degradation rate of 95%.
　　Degree Year: 2010