Preparation And Photocatalytic Activity Of Nano TiO₂ Flims By Molecular Self-assembly Method

Photocatalysis,which is green and environmental friendly technique,possessing a great practical value of environmental control.Titanium dioxide is the most secure and stable semiconductor material in this field.However,the nano TiO₂exists several problems in practical production,such as narrow spectral response range,powders reunion easily,photo-generated electron-hole,which limits its industrialization.So it is sigficant to develop a industrial method which is suitable for the preparation of TiO₂ photocatalytic materials.In this study,the supported TiO₂film material and FeOOH-TiO₂ composite membrane material are prepared by using the self-assembly method.The influence of preparation conditions and the photocatalytic properties of the material are discussed.1.The self-assembled monolayers?SAMs?are prepared by using silica glass substrate.Studies have shown that SAMs with?-HS?as surface functional group performed better photocatalysis compared with that of?-SO₃H?.The optimum concentration of silane coupling agent for preparing?-HS?SAMs is 1%(V_MPTMS:V_{Methylbenzene}).The optimum conditions of preparing this film TiO₂ is that the concentration of TiCl₄ is 0.15mol/L,pH value is 1,reaction time is 4h,reaction temperature is 70?and TiO₂ showed anatase phase.Fe³⁺/TiO₂ performed the best when the concentration of Fe³⁺is 0.20%.2.TiO₂/AC and TiO₂/zeolite are prepared by guiding of?-HS?SAMs and the TiO₂ showed both anatase phase.TiO₂/AC showed better photocatalytic property compared with TiO₂/zeolite.Whereas TiO₂/AC showed little difference of photocatalytic properties to methyl orange compared with TiO₂/zeolite.3.FeOOH-TiO₂ composite membrane materials are prepared under the system of?NO₃?₃-HNO₃ and FeCl₃-HCl respectively with silica glass as the substrate.FeCl₃-HCl system performed better photocatalysis than Fe?NO₃?₃-HNO₃ system.Photocatalytic preformance of the composite membrane is preferable when FeOOH is at the outer surface and the optimum concentration of ferric salt is 40mmol/L.4.We studied photocatalytic performance of four kinds of materials as follows,silica glass film based TiO₂ and Fe^3+/TiO₂thin films,FeOOH/TiO₂ and TiO_2/FeOOH composite film with methyl orange as the targeted pollutants.FeOOH/TiO₂composite film showed the best photocatalytic properties to methyl orange.TiO₂ and Fe^3+/TiO₂thin films showed the best performance for repeated used.In analog optical environment.They are all in line with the first-order reaction kinetics in the photocatalytic degradation of methyl orange under the circumstance of nature light.