Study On Structural Design And Photocatalytic Properties Of TiO₂ Based Composite Materials

With the acceleration of industrialization,environmental problems are getting increasingly serious and then the semiconductor photocatalytic technology to solve water pollution came into being.The principle of photocatalytic process is that a electron hole pairs of semiconductor material are excited when irradiated by light with certain energy.Subsequently,a series of redox reactions take place and the organic pollutants adsorbed on the surface of the material are degraded to CO₂ and H2 O in achieving water purification treatment.Titanium dioxide?TiO₂?is widely studied and applied due to its high photocatalytic activity,stability,oxidation resistance,environmental protection and other advantages.But the photocatalytic activity of TiO₂ is reduced because of its wide band gap,narrow range of photo-responsive and the high probability recomb ination between electron and hole,leading to further restrictions for TiO₂ application.At the same time,the current photocatalytic technology to solve environmental problems are also faced with many barriers,such as high costs control,low catalytic efficiency,narrow light response range,secondary pollution,etc.How to further improve the application of TiO₂ photocatalytic technology? This paper aims to develop a new kind of efficient and environment friendly TiO₂ composite photocatalyst,based on the structure design of composites TiO₂ modification and the photocatalytic application.Firstly,rod-granular attapulgite?ATTP?/TiO₂/Ag₃PO₄ three-phase composite photocatalyst is synthesized through the method of two step ion adsorption based on good adsorption and structural properties of ATTP.The photocatalytic performance of three-phase photocatalyst for the degradation of Luo Danming B solution under the condition of visible light irradiation will be studied,The results showed that the degradation rate of three-phase photocatalyst has reached 100% after 20-minutes photocatalytic reaction,and it still showed high photocatalytic activity after being reused 5 times.A series of spectral analysis also confirms that the range of spectral response for three-phase composite photocatalyst is wider than that of other samples.Additionally,TiO₂ inverse opal photonic crystal films with different pore sizes on FTO substrate via the preparation process of hard template,and then a layer of In₂O₃ quantum dots was adsorbed.Based on the photocatalysis degradation reaction oforaganic dye,it is found that the 337-nanometer IO-TiO₂-In₂O₃ prepered by polystyrene microspheres showed higher photocatalytic activity compared to the other samples.Due to the introduction of photonic crystal periodic pore structure,on one hand it increases the specific surface area of film,and on the other hand it increases light scattering which is helpful to the absorption of light.The introduction of TiO₂-In₂O₃ heterojunction is beneficial to the separation efficiency of electron hole pairs and the increase of attachment probability of holes,and thus improves the photocatalytic efficiency.