Preparation And Characterization Of TiO₂ Composite Nanostructures

Titanium dioxide(TiO2), as a new wide band gap semiconductor, its application covers the photocatalysis, gas sensor, photochemical synthesis, electrically induced discoloration, solar cells, lithium-ion batteries and other fields. A single TiO2 material often cannot meet the needs of actual application, so the composition or surface modification of TiO2 materials and preparing TiO2 materials with large specific surface area and various special morphologies is of great theoretical and practical application value to improve the performance of TiO2 materials and broaden the application field of TiO2. In this paper, titanium dioxide(TiO2) based composite nanostructures with different morphologies were synthesized vie hydrothermal method and other chemical methods. A variety of analysis methods were used to characterize the morphology and physical properties of the resulting samples, and the following main results were obtained:1. 3D urchin-like TiO2/Ag3PO4 heterostructures were synthesized via a simple wet chemical method and continuous ion layer adsorption method. The crystalline structure and visible light absorption properties have been investigated. The results show that the Ag3PO4 nanoparticles were successfully deposited onto the urchin-like TiO2 microspheres and the resulting TiO2/Ag3PO4 heterostructures exhibited enhanced visible light absorption properties as compared with single nanostructures2. TiO2 nanobelts were prepared in the alkaline solution through the hydrothermal method, then CuO nanoblades were coated on the surface of TiO2 nanobelts with a simple liquid phase synthetic method. The morphology, crystal structure and optical absorption properties of the samples have been characterized.Experimental results show that after coated with CuO, the heterostructure has an obviously enhanced visible light absorption performance than pure TiO2 nanotubes,moreover the band gap of the heterojunction has been obviously narrowed.3. TiO2/graphene composite structures were synthesized by one step hydrothermal method. The crystal structure, microstructure, light absorption properties and room temperature luminescent properties of the sample have been characterized. Experimental results of the samples showed that TiO2 nanobelts and graphene is in intimate contact with each other. The light absorption results of composite samples show that the more content of graphene, the stronger visible light absorption and the narrower band gap of the composite samples. Fluorescence test results of the samples show that the more content of graphene, the lower the luminous intensity of composite sample. The reason of weakened luminous intensity of the samples was that the formation of heterojunction has effectively inhibited the recombination of electron-hole pairs in the composite samples, thus reducing its luminous intensity.4. Yellow TiO2/SnO2 nanoparticles were synthesized by a simple chemical synthetic method and hydrothermal method, and the microstructure, crystal structure,light absorption performance and luminescence properties of the samples have been characterized. The light absorption test results of the samples show that the light absorption properties of TiO2/SnO2 composite nanoparticles are better than pure yellow TiO2 and SnO2, and the band gap is narrower than both pure samples.Fluorescence test results show that the luminous intensity of composite samples were weaker than pure TiO2 and SnO2, it is because the yellow TiO2 and SnO2 heterojunctions have inhibited the recombination of electron- hole pairs, thus reducing the luminous intensity of the composite samples. Photocatalytic experiment results show that photocatalytic activity of the TiO2/SnO2 composite nanoparticles is obviously better than pure yellow TiO2 and SnO2.