Preparation, Modification Of TiO₂Nanomaterials And Their Photocatalytic Performance Study

To date, with the development of textile industry and the abuse of personal careproducts, pesticide, surface active agent and drugs, a large amount of wastewater hasbeen discharged into rivers, causing serious threat to human survival. The common usedmethods for wastewater treatment includs physical process, chemical treatment, physicaland chemical treatment and biological treatment. Semiconductor photocatalytictechnology is an emerging approach for wastewater treatmen in recent years. The basicprinciple is to use semiconductor photocatalytic materials, combined with certain energyof light, electron-hole pairs were inspired, and the water and pollutant moleculesadsorbed on the surface of semiconductor accept the electronic-hole pair inspired by thelight, causing a serious of oxidation-reduction reaction, degrading the toxic and coloredpollutants into non-toxic or low toxicity products. Among various catalysts, TiO2photocatalyst is the most active studied due to its high chemical stability, resistance tocorrosion, strong oxidation, light catalytic reaction driving force, high photocatalyticactivity, non-toxic and low cost, which can realize and accelerate the endothermicchemical reaction on the surface of TiO2under irradiation. Unfortunately, the largebandgap and high electron hole recombination limit the photocatalytic efficiency. Toovercome these shortcomings, the modification of TiO2nanomaterials is of greatimportant. Surrounding the direction, our mainly works are listed below:(1) Well-ordered TiO2nanotubes array was prepared by anodic oxidation method inthe mixture electrolyte of water and glycerol. The influence of synthesis parameters (suchas electrolyte composition, anodic oxidation time and voltage etc.) on the morphology ofTiO2nanotubes array was discussed. For the bamboo-type TiO2nanotubes array appearedin the experiment, we investigated the influence of synthesis parameters and proposed thepossible formation mechanism of bamboo-like TiO2nanotubes array. For the TiO2nanotubes array prepared under different anodic oxidation time and voltage with differentnanotube length and diameter, we investigated the photocatalytic performance of TiO2nanotubes array with different morphology by photocatalytic degradation of alizarin red. Besides, the influence of different crystal type on the photocatalytic performance of TiO2nanotubes array was also investigated by photocatalytic degradation of alizarin red.(2) Zr doped TiO2nanotubes array were prepared by electrochemical depositionmethod. The optimal deposition conditions were found out by investigating differentdeposition voltage and electrolyte concentration; the optical absorption property of Zrdoping TiO2nanotubes array was investigated by UV-vis diffuse reflectance spectrum;the photocatalytic performance was investigated by photocatalytic degradation of alizarinred under UV light irradiation.(3) TiO2/ZnO/CdS nanocomposite was prepared by heat treatment method andsuccession chemical deposition method. The optimal deposition layer was found out byinvestigating different deposition times; the optical absorption property was investigatedby UV-vis diffuse reflectance spectrum; the photocatalytic performance was investigatedby photocatalytic degradation of alizarin red under UV light irradiation.(4) TiO2nanoparticles with the diameter of5nm and also fluorescence propertywere prepared by two phase hydrothermal synthesis method. On this basis, carbonhybridization TiO2nanoparticles were prepared in carbon nanoparticle solution. The XPSand PL tests indicated that there are electrons interactions exist between C and TiO2in C-TiO2nanomaterial, causing the great improvement in photocatalytic activity.(5) Ru-TiO2nanoparticles were prepared with the reaction of Ru nanoparticles andTiO2nanoparticles by two phase hydrothermal synthesis method. The optical absorptionproperty of Ru-TiO2nanoparticles were investigated by UV-vis diffuse reflectancespectrum; the photocatalytic performance was investigated by photocatalytic degradationof methylene blue under UV light irradiation.(6) Au-TiO2nanocomposite was prepared by reacting TiO2nanoparticles withHAuCl4through hydrothermal synthesis method following by reduction with ascorbicacid. The loading amount of Au was adjusted by changing the amount of HAuCl4and theamount of Au loading was calculated by x-ray photoelectron spectroscopy; the electro-catalytic property during the oxygen reduction reaction was tested by cyclic voltammetrymethod; the photocatalytic performance was investigated by photocatalytic degradationof methylene blue under UV light irradiation. (7) TiO2nanosheets were prepared by hydrothermal method. The TiO2nanosheetswere washed with NaOH solution. The photocatalytic performance of TiO2nanosheetsbefore and after washed with NaOH solution was investigated by photocatalyticdegradation of methyl orange, methylene blue, rhodamine and methyl violet under UVlight irradiation. The photocatalytic activity of F on the TiO2nanosheets surface todifferent dyes was studied.