【作者】 步绍静；

【导师】 靳正国；

【作者基本信息】 天津大学 ， 材料学， 2003， 硕士

【摘要】 本实验分别以TEOT和TiCl4为原料，加入高分子表面活性剂（DEA、三嵌段共聚物EPE）作模板，合成了高有序度、高比表面、热稳定性好的纳米晶TiO2多孔薄膜。对溶胶—凝胶过程发生的物理化学变化进行了系统的分析，确定了溶胶—凝胶的形成条件。考察了各种工艺参数对TiO2薄膜的微观结构及性能的影响，同时对PEG和三嵌段共聚物EPE的孔结构形成机理进行了初步的探讨。络合剂的加入可以有效地抑制TEOT的强烈水解，使钛溶胶体系更加稳定，其中由DEA作络合剂所得溶胶合成的纳米TiO2薄膜具有较好的孔结构，比表面积为72.5m2/g。纳米晶TiO2多孔薄膜孔径大小和分布密度与模板剂PEG的添加量和分子量有关。低分子量下薄膜孔径小且孔密度较高，分子量增大易使孔密度降低；孔径和孔密度都随PEG添加量的增加而增大。nH2O/nTEOT的比例及络合剂的加入量对薄膜表面形貌有重要影响。热处理制度是控制薄膜微观结构的一个工艺因素。实验得出，为获得完整的薄膜多孔结构，应该在焙烧过程中保持低的升温速率。PEG在多孔结构的形成过程中，以液晶模板机理和协同作用机理为主。 以TiCl4为溶胶前驱体、EO20PO70EO20为模板剂，在非水溶液条件下制备了高度有序的纳米晶TiO2介孔薄膜。薄膜具有均一的介孔孔径，约为10nm，薄膜较宽的无机壁厚（约10nm）显著提高了介孔结构的热稳定性。其BET比表面积为150m2/g，使纳米晶TiO2薄膜可以获得优异的光电化学性能。更多还原

【Abstract】 Highly-orderd Nanocrystalline TiO2 porous films with high specific surface area and high thermal stability were synthesized using organic surfactant(PEG, triblock polymer-EPE)as template. The physical and chemical changes during the sol-gel process were analyzed systematically and the condition for the formation of sol-gel was determined. The effects of processing parameters on the microstructure and properties of the titania films were studied and the templating mechanism of the PEG and EPE was discussed fundamentally. The addition of complexing agent effectively restrains the intensive hydrolysis of TEOT, which is helpful to get more stable titanium sol-gel. The nanocrystalline titania films from sol-gel with DEA are highly porous with high surface area (72.5m2/g). The size and density of pores are related to the quantity and molecular weight of the template. The diameter of pores in the films synthesized by PEG with low molecular weight is smaller and the density is higher. Comparatively, the distribution of the pores becomes looser with the high molecular agent. Both of the diameter and distribution of the pores increase with the content of PEG. nH2O/nTEOT and the content of complexing agent have effects on the morphology of the films. The heat-treatment is critical to control the microstructure of the films. The experiment shows that it is very important to prepare porous films at lower heating rate.During the preparation of the films, PEG operates by Liquid-crystal-Templating mechanism and Cooperative formation mechanism.Highly ordered porous naocrystalline TiO2 films were synthesized using triblock polymer EO20PO70EO20 as template and TiCl4 as precursor at non-aqueous condition. The pores in the films are uniform with diameter about 10 nm. The inorganic wall with thickness of 10 nm enhances the stability of the porous structure. The BET specific surface area of the film is 150 m2/g, which endues the films with excellent photo-electro-chemical properties.更多还原