Preparation And Property Research Of TiO₂-based Photocatalyst And CuBi₂O₄ Thin Films

With the development of industry and economy of human society, environmental and energy problems have been becoming more and more serious. Since Fujishima and Honda have reported the evolution of oxygen and hydrogen from a TiO2 electrode under the irradiation of light in 1972, photocatalysis was regarded as one of the most effective and economical ways to solve the environmental and energy problems.TiO2, with superior physical and chemical properties, is one of the most attractive semiconductor photocatalysts. However, its light quantum yield is still low, which is mainly caused by two reasons:①TiO2, with a direct band gap of 3.2 eV, responds only to UV light;②The photoinduced charge carriers recombined quickly. Also, TiO2 nanoparticles are difficult to be recycled, which is also a problem being settled.In recent decades, investigators have done a series of modification techniques to improve the light quantum yield of TiO2, such as dye sensitization, nonmetal doping, metal doping, noble metal loading, composite semiconductors and so on. In all of these methods, the composite semiconductors can solve the two problems stated above at the same time. And if we prepare sample into thin films, we can also solve the solidifying problems of photocatalysts. In this thesis, we have used the composite semiconductors method to resolve the above listed problems and improve the photocatalytic activity. The main content and results are discussed in the following sections.In part 1, we have synthesized Sb2O3/TiO2 composites by a chemical bath coprecipitation method. Compared with the pure Sb2O3 and TiO2, the photocatalytic properties of Sb2O3/TiO2 composites have been greatly improved. Besides, we also discussed the effects of synthesis conditions and composition on photocatalytics. 50% of MO were decomposed by the Sb2O3/TiO2 composites obtained in neutral solution and in proper acidic environment,100% of MO were decomposed in just 20 min. And the optimized composition for highly photocatalytic activities was also obtained. The designing of Sb2O3/TiO2 systems, with simple method and highly photocatalytic properties, lay the foundation for development of future photocatalysts.In part 2, uniform TiO2/Sb2S3 nanocomposites have been synthesized by a non-aqueous chemical bath deposition method. The influence of ultraviolet irradiation during growth on morphology of TiO2/Sb2S3 nanocomposites has been studied and for synthetized under UV irratation, highly photocatalytic activity was observed.In part 3, CuBi2O4 nano films have been growed by magnetron sputtering method. We have found out the optimum growing condition:substrate-cover glass, growing temperature-500°C; Based the optimum condition, we also studied the influence of sputtering powder on the sample structure and the light response. When the power exceeds 100 W, samples show (201) orientation; Compared with the Ag/CuBi2O4 samples growing on cover glass, the photocatalytic properties of Ag/CuBi2O4 samples growing on ZnO nanoarray have been a little enhanced, but the results need more investigation.