【作者】 徐丽丽；

【导师】 陈玉清；

【作者基本信息】 山东轻工业学院 ， 材料学， 2008， 硕士

【摘要】 本文针对当前TiO₂薄膜的低温制备及固化技术相对落后的研究开发现状,以及当前自清洁薄膜制备工艺复杂、能耗大的弊端,对溶胶—凝胶法低温制备TiO₂薄膜工艺进行改进,常温固化制得具有较高光致性能的透明TiO₂-SiO₂自清洁薄膜,薄膜与基板附着力强。以TiCl4、氨水、H2O2等为原料,通过水解、沉淀、胶溶、络合、回流等步骤低温制备纳米TiO₂水溶胶。采用正交试验法,以水溶胶对甲基橙的降解率为考察指标,对TiO₂水溶胶低温制备工艺进行优化,并研究各因素对水溶胶光催化活性的影响。结果表明:pH值对水溶胶光催化活性的影响最显著,其次是回流温度、回流时间,TiCl4与加入的蒸馏水体积比的影响最小。推荐优选工艺条件是pH值8⁹、回流温度80℃、回流时间8¹0 h、TiCl4与加入的蒸馏水体积比1:100。制备的水溶胶采用X射线衍射、扫描电镜、紫外—可见光吸收光谱等测试手段进行表征。结果表明:水溶胶中含有纳米针锐钛矿型晶粒,晶粒沿锐钛矿晶格c轴择优生长,形貌一致、分散性好;水溶胶的吸收边红移至470 nm;随回流时间的延长和回流温度的升高,水溶胶中锐钛矿型晶粒长大,水溶胶的光催化活性先提高再降低;80℃回流10 h的水溶胶光催化活性最好,25 W紫外灯照射下对10 mg/l甲基橙溶液60 min降解率达到87.7 %。采用环境扫描电子显微镜、原子力显微镜、傅立叶变换红外光谱、紫外—可见光吸收光谱等测试手段对浸渍—提拉法室温下在玻璃基板上制得的薄膜进行测试。结果表明:薄膜中粒子分布均匀,无孔洞,无龟裂;薄膜中颗粒粒径比水溶胶中TiO₂粒子粒径大得多,且形貌发生了变化,由针状变成了类球状;可见光区,TiO₂薄膜透过率均大于80 %,热处理使薄膜中粒子团聚或长大,会对薄膜透过率、光致性能产生不利影响;可见光区,TiO₂-SiO₂系列薄膜透过率均大于75 %,SiO₂摩尔分数为20 %的薄膜透过率接近100 %;TiO₂-SiO₂系列薄膜中,TiO₂和SiO₂分别单独成相,并有Ti-O-Si键形成,存在部分复合氧化物;薄膜表面呈现峰峦状结构,随掺杂量增加,粗糙度明显提高;TiO₂-SiO₂系列复合薄膜光催化活性随掺杂量增加有所下降;SiO₂摩尔分数为10 %和20 %的薄膜具有良好的超亲水性能;掺杂SiO₂使薄膜与玻璃基板附着力显著增强。更多还原

【Abstract】 At present, the low-temperature preparation and solidifying technology of TiO₂ thin film in our country fall behind in other countries. The industrialization production of self-cleaning thin film has some disadvantages such as complicated technology and too much energy consumption. In this paper, it was improved that TiO₂ thin film technology of Sol-gel method at low temperature, and transparency TiO₂-SiO₂ composite self-cleaning thin films with superior photo-induced property were prepared at room temperature. Films have a good adhesion with substrate.Nano-TiO₂ hydrosols were synthesized using titanium tetrachloride （TiCl4）, ammonia （NH3·H2O） and peroxide （H2O2） as raw materials by hydrolyzing, precipitating, peptizing, complexing and refluxing. With the degradation rate of methyl orange as indexes, the process was optimized by orthogonal design. The effect of different parameters on photocatalytic activity of hydrosols was studied. The results show that pH has a significant effect on photocatalytic activity, and the next is refluxing temperature and time. The effect of the volume ratio of TiCl4 and added distilled water is least. Suggested optimum process conditions is as follows: 8 to 9 of pH, 80℃of refluxing temperature, 8 to 10 hours of refluxing time and 1:100 of the volume ratio of TiCl4 and added distilled water.The hydrosols were characterized by X-ray diffraction （XRD）, transmitting electron microscope （TEM） and ultraviolet-visible absorption spectra （UV-Vis）. The results show that hydrosols contain needle-like nano anatase crystal grains, which grow along the c-axis, with homogeneous morphology, good dispersancy. Absorption edge wavelength of the hydrosols shifts to 470 nm. As the refluxing time lasts and refluxing temperature rises, crystal grain size of the hydrosols grows, but photocatalytic activity enhances in the beginning, and then reduces. TiO₂ hydrosol refluxed at 80℃for 10 h shows the best photocatalytic activity. Under 25 W ultraviolet light irradiation, 60 min degradation rate of 10 mg/l methyl orange is 87.7 %.TiO₂ thin films and TiO₂-SiO₂ composite thin films were prepared by dipping-withdrawing at room temperature. They were characterized by environmental scanning electorn microscope （ESEM）, atomic force microscope （AFM）, fourier transform infrared spectroscope （FTIR）, ultraviolet-visible absorption spectra （UV-Vis） and other means of testing. The results show that there is uniform distribution of particles in the films, which are no holes, no cracks. Grain size of particles in the films is much greater than that in the hydrosols, and morphology has changed from needle-like to approximate sphericity. Transmittance of TiO₂ films is more than 80 % in the visible region. Particles in the films reunion or grow up after the heat treatment, which will have a negative impact on film transmittance, photocatalytic activity and hydrophilic property. In the visible region, transmittance of TiO₂-SiO₂ composite thin films is more than 75 %, and transmittance of the film with 20 % of SiO₂ content （mol %） is nearly 100 %. In TiO₂-SiO₂ films, there are TiO₂ and SiO₂ phase separately, and Ti-O-Si bond, so there are some composite oxides. Films show mountain-range-like structure. Roughness markedly improves with the content of SiO₂ increasing. The more SiO₂, the lower photocatalytic activity of TiO₂-SiO₂ thin films. Thin films with 10 % and 20 % of the SiO₂ content have good super-hydrophilic property. Adhesion of the films and glass substrate enhances greatly by SiO₂ doping.更多还原