| Currently, with the word widely concern about energy shortages and environmental pollution problems, renewable energy’s utilization become growing population. Solar energy, which is agreen,environmental friendly, clean and renewable source, has sparked a great interest in scientific research. Photocatalytic technology is considered to be one of the most effective ways to utilization of solar energy. The photocatalyst as the core of photocatalytic technology is not only required to effectively absorb solar energy, promote photocatalytic reaction, but also has the feature of non-toxic, recyclable, easily synthesis, cheap and so on. With the rapid development of materials science, inorganic nanomaterials play an increasingly important role in photocatalysis fields. Semiconductor titanium dioxide (TiO2) nano-materials, which is easily synthesis, low toxicity, low-cost, high efficiency, high stability and environmental friendliness, is widely used in various type of photocatalytic reactions which is shown to be the extensively researched photocatalytic materials at present. However, because of the pure anatase TiO2 only responds to ultraviolet light due to the large band gap and use of sunlight is merely 3-5%, there also exist restrictions in photocatalytic applications. Therefore, composite, load and hybridization with other materials are studied by researchers so that it can improve its photocatalytic activity. Meanwhile, on account of the reunion of powder TiO2 nanoparticles, researchers try to build a hollow hierarchical structure of TiO2 to increase its surface area and the enrichment effect of reactants in photocatalytic reaction process to expose more catalytically active sites so that it can enhance the effective utilization of light energy which can improve the photocatalytic activity and stability finally.Hollow TiO2 (@TiO2) nano-catalytic material was prepared by sol-gel method firstly, and then impregnated by Ag+ions obtained@TiO2/Ag-AgCl nano-catalytic material in first part. The resulting@TiO2/Ag-AgCl nano-catalytic material has @TiO2 hierarchical structure, Ag-AgCl nanoparticles dispersed onto its internal and external surfaces uniformly. Since the Ag-AgCl nanoparticles having a strong surface plasmon resonance (SPR) effect, the resulting@TiO2/Ag-AgCl nano-catalytic material generated some response to visible light. Photodegradation of methyl orange and Rhodamine B are the evaluate model of @TiO2/Ag-AgCl nano-catalytic material’s photocatalytic performance. Studies have shown that, methyl orange and Rhodamine B are completely degraded in the 8 and 20 min respectively with @TiO2/Ag-AgCl nano-catalytic material which is superior to commercial P25. Its high photocatalytic activity is mainly due to Ag/AgCl nanoparticles on the@TiO2 surface which can be produced strong SPR effect. At the same time, Ag/AgCl nanoparticles can be polarized light induced charges which in favour of electron-hole separation, then enhance the light efficiency and accelerate the rate of degradation of organic dyes.The second part preparation of supported TiO2/Ag nanocatalysis material through hydrothermal situ etching by one-step method which take amorphous@TiO2 as reaction precursors, AgF and NaF as surface F etchant and noble metal. The resulting TiO2/Ag nano-catalytic material is well dispersed, Ag nanoparticles uniformly dispersed on the surface of TiO2, the morphology varies from ellipsoidal to cube during the AgF and NaF content change. Take 4-nitrophenol reduction and degradation of Rhodamine B as model reaction to evaluate the photocatalytic properties of TiO2/Ag nano-catalytic. Studies have shown that, TiCVAg nano-catalytic materials has high catalytic activity for the reduction of 4-nitrophenol because of the exposure active sites of Ag nanoparticles. Meanwhile, TiO2/Ag nano-catalytic material also showed high catalytic activity to the degradation of Rhodamine B which can be completely degraded within 8min. SPR effect produced by coupling Ag and TiO2 nanoparticles can effectively enhance the TiO2/Ag nano-photocatalytic properties. At the same time, due to the etching of F ions, the morphology of TiO2 changes can benefit to the exposure of anatase energy{001} plane which can produce more electron-hole pairs in photocatalytic process, and electron-hole pairs can combine with OH-to produce large amounts of hydroxyl radicals, accelerate the decomposition of organic dyes finally.The third part of this paper prepared hollow SnO2 (@SnO2) nanostructures by hydrothermal, and impregnated by Ag+ions obtained@SnO2/Ag-AgCl nanocatalytic material. At the same time, TiO2/M@SnO2 (M=Pd, Ag, Au and Pt) nano-catalytic material was prepared by loading noble metal nanoparticles on the surface of SiO2@TiO2 nanostructures which was prepared by hydrothermal method and then coated SnO2 on its shell through sol-gel method. The obtained TiO2/M@SnO2 catalytic material with double shell structures and dispersed well. Noble metal nanoparticles loaded between TiO2 and SnO2 shell has uniform size and uniform dispersion. The resulting@SnO2/Ag-AgCl catalytic material was preliminary evaluated by methyl orange and Rhodamine B photodegradation. Studies have shown that,@SnO2/Ag-AgCl nano-catalytic material can be completely degradation of methyl orange and Rhodamine B in the 3 and 7 min respectively, showing more excellent photocatalytic properties. |
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