Preparation And Performance Study Of Titanium Dioxide Nano-Materials And Composite Materials

Today's society is faced with the serious problems of global industrialization which are speeding up the consequent of environmental pollution and energy shortage. Photocatalytic degradation of pollutants is an effective method to solve the environmental problems. Titanium dioxide as a typical semiconductor photocatalyst, has the superior performance, such as chemical stability, high catalytic activity, rich source, cheap and no secondary pollution. In recent years, TiO₂ nanomaterial has attracted many researchers' attention. But the bigger forbidden band width and the lower quantum efficiency limit the development of titanium dioxide in the practical application. A large number of experimental results show that the study of the modification of TiO₂ can control its spectral response in the visible light range, restrain the composite risk of photon-generated carrier, and improve the quantum efficiency and light catalytic activity. This article studies the control of bath temperature, Ti³⁺ self-doping and the compound semiconductor impact on the surface morphology of the titanium dioxide, chemical composition, crystal structure and catalytic performance. The main results were as follows:?1?TiO₂ which is prepared by the direct hydrolysis method, belongs to anatase structure. Through the different water bath temperature to control the surface morphology of TiO₂, grain size and photocatalytic performance. When the water bath temperature is 15 ?, the absorption intensity and light catalytic activity of TiO₂ samples reached the maximum under UV and visible light. The self-doped Ti³⁺ of the pure TiO₂ samples were prepared by hydroxylamine hydrochloride?NH2OH · HCl? as a reducing agent, with ammonia?NH3 · H2O? as a medium conditions. According to the figure of methyl orange degradation efficiency, it is proved that Ti³⁺ self-doped samples showed the best photocatalytic performance with a moderate amount of ammonia.?2?The nano-sheet materials of CoS have advantage in adsorption properties, which is prepared by simple chemical bath. Controlling the temperature of water bath can change CoS surface morphology, the size of the sheet thickness and specific surface area, so as to achieve control of the adsorption of the sample performance. When the temperature reaches 120 ?, the shape of the CoS samples closer to flower, slice become the thinner, and showed the best adsorption performance.?3?Under the condition of 90? constant temperature, CoS nano materials are successfully prepared with adjustment to the dosage of surfactant PEG, which shows the high adsorption performance. According to the adsorption efficiency of organic dye methylene blue and heavy metal ions Pb2+ and Cd2+, it is known that the preparation of CoS nanomaterials showed the highest performance when the adding amount of PEG is 100 mg, and also can prove that no matter how much the amount of PEG joined, the adsorption performance were higher than that of under the constant temperature prepared the pure CoS samples.?4?CoS and TiO₂- CoS nano composite are successfully prepared by precipitation method. CoS shows stronger photocatalytic activity under the UV irradiation. Compounding with the titanium dioxide can significantly improve the photocatalytic activity of TiO₂, this is due to the composite structure can trigger fast separation of photon-generated electron-hole pair.