Study Of Photoelectric Properties Of TiO₂Nanomaterials Modified By LiF

Nanocrystalline TiO2semiconductor material has been widely applied due to its high catalytic activity, low-cost, abundance in resources, and long-term stability. Among various applications, photocatalyst is one of the most promising functionalities because of its strong capability in degrading wide ranges of organic substances. However, due to its wide band gap(3.0～3.2eV), TiO2only shows excellent photocatalytic activity under UV light, which means that only3-5%solar energy, could be utilized during photocatalytic process. Studies show that non-metallic ion doping and modifying can effectively improve the photocatalytic efficiency of TiO2in visible light range. This article mainly focused on hydrothermal preparation of LiF modified TiO2nanoparticles, and exploring its photocatalytic performance enhancements. The hydrogen sensing characteristics of TiO2thin film modified by LiF were also systematically investigated. The main research results are shown as follows:1, Anatase TiO2nanocrystallines were obtained by hydrothermal method, LiF was used to modify the photocatalytic property of TiO2powders by hydrothermal treating of LiF and TiO2mixed powders. The hydrothermal treated LiF-TiO2powder has shown strong absorbability to organic dye methylene blue (MB). With a mole ratio bigger than0.5, nearly90%of dye were absorbed onto the surface of the photocatalyst. After being annealed in air at400℃for2hours, the TiO2catalyst further displayed good photocatalytic activity under visible light to MB.2, A series of samples were obtained by hydrothermal treatment of TiO2powder and LiF saturated solution with different LiF and TiO2mole ratios. Photocatalytic property of the samples was tested by degredating of methyl blue. The best photocatalytic activity was realized with LiF and TiO2molar ratio of1:1, the degradation rate is nearly eighty percent after250minutes.3, Hydrogen sensing characteristics of TiO2thin film modified by LiF were systematically investigated. It is found that the LiF modified TiO2thin films has sensing response at room temperature, which suggests that it could be used as room temperature hydrogen sensor. Sensing mechanism was then further discussed.