Preparation Of Nano Metal Oxide And Study On Its Photocatalytic And Luminescent Properties

With the continuous development of society and the advancement of industrialization, Chemical wastes, especially benzene, Nitrogenous organic compounds, sulphide and PAHs pollutions have become increasingly serious, and has gradually penetrated into industry, agriculture and other fields, endangering human health. In nowadays when people’s environmental awareness raised, the sustainable development and ecology civilization construction are establishing, the use of solar energy as a driving force of photocatalyst can effectively degrade organic pollutants, improve the environment, and basically solve the energy and environmental problems facing human beings, attracting attentions and favors of more people.TiO2material, with low cost, no secondary pollution, strong oxidation ability, coloring ability, reducing power, resistance to chemical corrosion, high stability, good dielectric properties and photocatalytic degradation of toxic pollutants, attracts attention of many research workers and possesses great and wide potential of application. With the development of nanotechnology, and discoveries of surface effect, volume effect, quantum size effect, macroscopic volume effect of nanometer materials, the application of titanium TiO2nano material continues to expand. However, the fact that wide band gap semiconductor materials of TiO2of light response of narrow range can not effectively utilize visible light hinders further development of TiO2. Therefore, to improve the quantum efficiency of TiO2, extend light response range and apply the use of clean energy in visible light have become a bottleneck problem. In this paper, the main work for solving the bottleneck problems is included as follows:1. By controlling the electrospinning precursor solution composition, electrostatic spinning parameters and spinning fiber heat treatment process, we have successfully made the TiO2possessing the nanowires and nanotubes structure. The surface of nanowire TiO2is smooth and has a large ratio of length to diameter. The pipe wall of TiO2nanotubes, with even distribution of TiO2nanotubes, is composed of TiO2nanoparticles, and possesses obvious porous structure. We have studied the efficiency of the photocatalytic decomposition of organic dye RhB under UV light. Results show that both TiO2nanowires and nanotubes exhibit, nice photocatalytic performance, in which the photocatalytic property of porous TiO2nano tube is a bit better than that of TiO2nanowires. That is because a build-in electric field has formed within the porous structure of TiO2nanotubes and anatase, rutile phase heterojunction.2. Relatively pure nanostruclure material of TiO2are prepared by electrospinning at first, and TiO2with different crystal are produced by different annealing tcmpcraturcs, and finally, TiO2nanowires are prepared by impregnation of V2O5, So that TiO2forms a heterojunction without affecting the TiO2crystalline phase under the condition of two times of annealing. Subsequently, the photocatalytic properties have been investigated. Conclusions under visible light are as follows:(1) The formation of V2O5and TiO2heterojunction has greatly improved the photocatalytic efficiency.(2) Different crystals of TiO2phase have little effect on TiO2and V2O5photocatalytic efficiency.3. The preparation of nuclear shell structure of V2O5@TiO2heterojunction have been studied, and explored the various experimental conditions such as, surface active agent, precursor ratio and effect of pH value on the structure and morphology of samples. Study on the effect of V2O5@TiO2heterojunction and its degradation characteristics of organic matter of different compositions of morphology have been conducted, and we have found that a molar ratio of1:5between vanadium and titanium is the best proportion for the maximum decomposition rate of (RhB) in a short period of time.Rare-earth-doped wide band gap semiconductors have attracted a great deal of attention recently due to its unique luminescence features of RE ions and properties of semiconductors as well as applications in biolabels, opticaldevices, lighting, and displays. The large band gap of the host material allows larger RE solid solubility and higher luminescence efficiency.MoO3is an important n type transparent conductive oxide, with excellent reversible photochromism and high optical contrast. There are three basic polymorphous of MoO3, i.e., orthorhombic MoO3(a-MoO3), monoclinic MoO3(P-MOO3), andhexagonal MoO3(h-MoO3), in which a-MoO3is the thermo dynamically stable phase. α-MoO3has been demonstrated to have promising applications in catalysis, gas sensing, field emission, lithium-ion batteries, photochromic devices, and electrochromic devices. Therefore,α-MoO3with a wide band gap can be an attractive host for RE elements. But its high resistivity and hinder the development of. This paper tries to dope Er in MoO3, and to study its luminescence and improve its conductivity, in order to commercially apply to the rare-earth-based visible optoelectronic devices.In summary, the orthorhombic phase MoO3materials and1%,3%, and5%Er-doped MoO3powders have been prepared through solid phase synthesis, and we have studied the morphology structure and luminescence of MoO3material. The grain sizes of crystallites are51,41,40, and44nm respectively corresponding to the undoped,1%,3%, and5%Er-doped MoO3powders. Besides the common stretching, deformation, and lattice modes resulting Raman peaks, the Er-doped MoO3show more obvious other peaks when the Er concentration increases. The intense green photoluminescence ascribed to Er3+intra-4f shell transitions were observed at room temperature. In view of the PLE spectrum, a defect-assisted energy transfer mechanism from MOO3host to Er3+ions is proposed. These results suggest that MoO3may be a suitable host material for rare-earth-based visible optoelectronic devices.