Preparation And Photocatalytic Property Of Sno₂ Nanocomposite

With the development of industrial society, the living environment has been destroyed seriously due to the large amount of waste gas and water. Semiconductor photocatalysis can oxidize hydrocarbon, dye and pesticide residues in water or air to H2O, CO2 and other small molecules, with some useful advantages, such as high activity, safety and cheap. Therefore, the semiconductor photocatalysis is a topic point in environmental purification field. As a common semiconductor photocatalyst, the nano-TiO2 has some defects, such as wide band gap, electron-hole easy to combine invalidly, low utilization ratio of solar energy and so on. Currently, two or more compound semiconductor photocatalysts could give high catalytic activity, and extend useful spectral range from ultraviolet region to visible light, therefore, the utilization ratio of sunlight is increased.In this paper, SnO2 nanoparticles were first prepared by sol-gel method, in which the SnCl2 and CTAB were used as Sn source and soft template respectively. Then, the SnO2/TiO2 and CuO/SnO2/TiO2 nanocomposites were synthesized. Furthermore, the effects of different factors on the photocatalytic activity were studied, and the formation mechanism and the photocatalytic mechanism of the product were discussed.Main work as follows:1. Preparation and photocatalytic property of SnO2 nanoparticlesIn the presence of the cetyltrimethylammoniumbromide (CTAB) soft template, the SnO2 nanoparticles were prepared by a sol-gel method. The product was characterized by SEM, XRD, IR,UV-vis and PL. The results show that the nanoparticle have a typical rutile structure, with about 17 nm in size. The photocatalytic activity of SnO2 nanoparticles was studied by sunlight degradation for methylene blue and alizarin red. In addition, the formation mechanism and the photocatalytic mechanism of SnO2 nanoparticles were discussed.2. Preparation and photocatalytic property of SnO2/TiO2 nanocompositeBy using CTAB, SnCl2 and Ti(OC4H9)4 as soft template, Sn source and Ti source respectively, the SnO2/TiO2 nanocomposite was prepared by a sol-gel method. The nanocomposite as-obtained was characterized by XRD, SEM, IR and UV-vis. The results show that the SnO2/TiO2 nanocomposite was composed of anatase crystal TiO2 and rutile crystal SnO2 with 15 nm in size. Under sunlight, the photocatalytic activity of the SnO2/TiO2 nanocomposite was determined by using the methylene blue and alizarin red as simulation pollutants. The results indicate that SnO2 could enhance the photocatalytic activity of the TiO2. In addition, the formation mechanism and photocatalytic mechanism of SnO2/TiO2 nanocomposite were discussed.3. Preparation and photocatalytic property of CuO/SnO2/TiO2 nanocompositeIn the presence of the CTAB soft template, the CuO/SnO2/TiO2 nanocomposite was prepared by a sol-gel method. The nanocomposite as-obtained was characterized by XRD, SEM, IR and UV-vis. The results show that the CuO/SnO2/TiO2 nanocomposite has a spherical monoclinic structure, with about 11 nm in size. The photocatalytic activity of CuO/SnO2/TiO2 nanocomposite was studied by photodegradating methyl orange. In addition, the effect of various factors, such as CuO content, solution acidity, H2O2, on photocatalytic degradation was discussed.