Synthesis And Study On The Photocatalytic Properties Of Niobium Doped Mesoporous Titanium Deoxide

In the past decade, mesoporous materials have been of great interest as catalysts because of their unique textural and structural characteristics. Mesoporous semiconductor oxides as potocatalysts to degrade organic substances have been a hotspot As the primary material of potocatalyst, titania (T1O2) has been considerably investigated and shown to be very effective for technological importance including environmental pollutant cleanup and photocatalysis applications for it's chemical stability and close friend to environment. In recent years, It is one of major directions to modify TiO₂ by mixing titania with other oxide semiconductor oxides.In this article, Mesoporous TiO₂ was was synthesized via a combined sol-gel process with surfactant- assisted templating method, hexadecyltrimethylammonium bromide(CTAB) as template, Ti(OC₄H₉)₄ as predecessor, triethanolamine as hydrolysis retarding agent and ethanol as solvent. Experiments decided on synthesis condition of Mesoporous TiO₂ through investigating calcined temperature, amounts of surfactant, rate of heating, etc. Then, niobium was added the mesoporous system to synthesize mesoporous Nb₂O₅-TiO₂, with niobium oxalate as predecessor.The resulting products were methodically characterized by TG-DTA, XRD, FT-IR,and diffuse reflectance UV-Vis spectra. The results showed that the mesoporous titania could be synthesized by calinced temperature at 400°C, and its mesoporous structure would be destroyed beyond 400°C. A suitable proportion between the surfactant and the predecessor will be essential. so did hydrolysis retarding agent and the predecessor. one of choice would be Ti/CTAB=3,TEA/Ti=3. The lattice parameter of TiO₂ changed after niobium being added. At the same time, The distance between (101) crystal faces of the simples were increased and absorb edge was blue shift. With amounts of niobium increasing, the mesoporous structure stability of the composite oxides was declined.We evaluated photocatalytic activity of mesoporous TiO₂ and Nb₂O₅-TiO₂ composite oxides by using phenol as the objective degrading substance. The results showed that the initial concentration of the solution, contents of the catalyst and the process condition for mesoporous sieves' synthesis affected the photocatalysis activity. The small amount adding of Nb₂O₅ hardly affected photocatalysis activity of TiO₂.However, with amounts of Nb₂O₅ increasing, absorb edge of the simples was blue shift and ban band increased so that photocatalysis activity of the composite oxides was declined.