SBA-15空间限制纳米TiO2颗粒的制备及其光催化性能研究

将硫酸钛浸渍到SBA-15孔道中, 经升温原位沉淀、焙烧得到纳米孔道中均匀分散的锐钛矿相TiO2. 用TEM, BET, XRD, SAXD, Raman, UV-Vis漫反射吸收光谱, XPS, XRF等方法对材料进行了表征. 表征结果表明, 改性后的SBA-15仍保持着有序的孔道, TiO2颗粒较均匀地分布在SBA-15孔道内部, SBA-15孔道合适的纳米尺寸对TiO2颗粒的长大起到较好的限制作用, 从拉曼光谱和XPS数据上看, 未发现有Ti—O—Si键形成, 氧化钛多以TiO2的形式沉积在载体上; 紫外光下的甲基橙光降解结果表明, TiO2颗粒大小和含量对光催化活性均有较大影响, 6～7 nm左右的TiO2颗粒有最佳的光催化效果. 20% TiO2/SBA-15样品焙烧后五次重复利用效果基本得以保持.

Photocatalytic Activity of Nano-size TiO2 Synthesized by Restricting the Particles within Channels of SBA-15

Nanocrystalline anatase TiO2 limited within the mesoporous channels of SBA-15 has been prepared by in-situ hydrolysis precipitation of Ti(SO4)2 solution and subsequent calcination. The as-synthesized samples were characterized by TEM, BET, XRD, SAXD, Raman, UV-Vis, XPS and XRF techniques, and the results indicated that the nano-TiO2 particles were restricted within the channels and dispersed uniformly without blocking the pores. The Raman and XPS data indicated that most TiO2 particles were deposited on the support without forming a Ti—O—Si bond. The activities of the samples were evaluated by the photo degradation of methyl orange under UV light. The results showed that the TiO2 contents and the size of the particles on the support of SBA-15 affected the catalytic activity obviously, and the samples with TiO2 particle sizes of about 6～7 nm showed the best catalytic activity. Little difference of the activity was observed between the fresh sample and the sample used for 5 times.