宏观尺寸大孔-介孔TiO2-SiO2光催化剂的制备及其在染料降解中的应用宏观尺寸大孔-介孔TiO2-SiO2光催化剂的制备及其在染料降解中的应用

以柱撑式环氧树脂大孔聚合物为模板，制备宏观尺寸的大孔-介孔SiO₂；以其为载体，通过钛酸四丁酯原位水解和高温焙烧制得大孔-介孔TiO₂纳米晶-SiO₂复合材料。应用SEM、TEM、XRD、FTIR和N₂吸附-脱附法对材料进行表征。以偶氮荧光桃红为模拟污染物，用氙灯模拟日光光源，考察了不同条件下大孔-介孔TiO₂-SiO₂的光催化性能。结果表明，大孔-介孔SiO₂具有三维连续贯通的大孔孔道，孔壁为连续的纳米SiO₂薄膜；TiO₂纳米晶以纳米薄膜的形式均匀地原位生长在SiO₂纳米薄膜的两侧，得到的复合材料孔壁上存在丰富的介孔。当焙烧温度为600℃、TiO₂的负载量为15.7wt%、染料溶液浓度为10 mgL-1且pH为3时，大孔-介孔TiO₂-SiO₂光催化剂对污染物的光催化降解效率最高，而且具有良好的重复使用性。 

Preparation of macro-sized macro-mesoporous TiO2-SiO2 photocatalyst and its application in dye degradation

The macro-sized macro-mesoporous SiO₂ was prepared by using a pillared epoxy resin macroporous polymer as the template and it was used as support to prepare macro-mesoporous TiO₂ nanocrystalline-SiO₂ composite through an in situ hydrolysis of tetrabutyl titanate and a subsequent calcination at high temperature. The macro-mesoporous TiO₂-SiO₂ samples were characterized by SEM, TEM, XRD, FTIR and N₂ adsorption-desorption. Using azophloxine as a simulated pollutant, the photocatalytic activity of the macro-mesoporous TiO₂-SiO₂ was studied under the sunlight irradiation simulated by Xenon lamp under different conditions. The results show that the macro-mesoporous SiO₂ has 3D continuous pass-through macropore structure and its pore wall is continuous SiO₂ nano-film. TiO₂ nanocrystallines, in the form of nano-film, in situ grow uniformly on both sides of the nano SiO₂ film, and abundant mesopores were observed on the pore wall of the obtained macro-mesoporous TiO₂-SiO₂ composite. The macro-mesoporous TiO₂-SiO₂ photocatalyst exhibits the best activity for photocatalytic degradation of pollutant from the macro-mesoporous TiO₂-SiO₂ composite containing 15.7wt% of TiO₂ calcined at 600℃, under the conditions of azophloxine concentration 10 mgL^-1 and pH of 3. The macro-mesoporous TiO₂-SiO₂ photocatalyst also has good reusability.