Prepration Of CuS/TiO₂ Core/Shell Nanostructure Materials And Research On Its Ultraviolet Characteristics

With the development of nano-materials research, new composite nanostructure materials have become a hot topic. For a long Time, TiO₂ has been used in ceramics, paints, cosmetics and electronics. In recent years, with the discovery that hydrophilicity of TiO₂ increases in UV light, TiO₂ began to be popular in photodegradation, photocatalysis, solar cells and other areas. And because of its low toxicity, low-cost, stability, etc., is considered to be the only large-scale industrial materials. TiO₂ is a typical n-type semiconductor material, when absorbing light energy greater than the band gap, TiO₂ will be excited. However, due to the band gap of TiO₂ is large（anatase 3.2 e V, rutile 3.0 e V）, it can only make use of ultraviolet light（less than 400 nm） light. There are only 4%-5% of the energy of the energy in sunlight is ultraviolet light, so the solar energy utilization efficiency is low. Currently there are several major ways to improve the UV utilization of TiO₂, including ion doping, precious metal deposition, dye-sensitized, regulatory structure and semiconductor composite. Among them, because of the obvious effect of structure controlling, low-cost, non-polluting, semiconductor compositing has become the most promising approach. On the other hand, with the development of colloid chemistry and nanomaterials, composite shell structure exhibits some special properties than single particles. Especially nano-shell structure exhibits more and more different nanometer effects, which makes the preparation of compound semiconductor nanomaterials become an important idea to modify TiO₂.This paper describes a low temperature（60℃） two-step chemical method to coat TiO₂ on the surface of the core Cu S, which means a novel Cu S / TiO₂ core / shell structure nano composite material. By XRD, SEM and Raman, the Cu S / TiO₂ core / shell structure nano composite materials was characterized and analyzed. The results showed that controlling the ratio of Cu and S atoms in the reactants can be successfully prepared both spherical and flower-like Cu S about 100 nm. The flower-like Cu S nanocrystals is made up of lamellars with the thickness of ²0 nm. Both two kind of Cu S can be used as the substrate and TiO₂（mixed crystal rutile and anatase phase） as the coating layer.Subsequently, the ultraviolet light absorption characteristics and photocatalytic activity of the Cu S / TiO₂ composite nanostructures are researched. Compositing different levels of compound semiconductors can regulate the moving direction of the electrons when semiconductors stimulated. This approach separates the electron and hole pairs effectively to improve photocatalytic of TiO₂. Further compared the catalytic activity and catalytic efficiency of the spherical Cu S / TiO₂ core / shell composite nanostructures and flower Cu S / TiO₂ core / shell composite nanostructures, we found that due to the large surface area of the flower-like Cu S as the core, the effective area per unit volume can be excited TiO₂ increases. The result is thus simultaneously through structural control to further enhance the catalytic activity of TiO₂.