双介孔结构的纳米TiO2/I2复合材料的制备及其可见光催化性能

以钛酸丁酯为前驱体, 碘溶胶为碘源, 在室温下采用水解沉淀法制备了单质碘和纳米TiO₂复合的双介孔结构光催化剂(M-I₂-TiO₂). 采用X射线衍射(XRD)、透射电子显微镜(TEM)、比表面分析(BET)、紫外-可见(UV-Vis)漫反射光谱和傅里叶变换-红外光谱(FT-IR)对M-I₂-TiO₂进行了表征. 以次甲基蓝(MB)溶液为模拟废水, 对M-I₂-TiO₂的光催化性能进行了评价, 研究了不同热处理温度对光催化活性的影响. 结果表明, M-I₂-TiO₂在可见光区有显著的吸收, 300 ℃热处理得到的样品比表面积高达227.6 m²/g, 600 ℃热处理所得样品的比表面积仍高达111.8 m²/g, 而400 ℃热处理所得样品具有最好的光催化降解性能. 双介孔结构纳米TiO₂/I₂复合材料的光催化降解性能显著高于相同方法制备的纯TiO₂和Degussa P-25商业产品. 催化剂经6次重复使用其光催化活性基本保持不变.

Preparation and Visible Light Photocatalytic Activity of Bimodal Mesoporous TiO2/I2 Composite Nanomaterials

An accessible, template-free process to fabricate bimodal mesoporous TiO₂/I₂ composite nanocrystallites was developed by using tetrabutylorthotitanate TiO(C₄H₉)₄, TBOT] and iodine hydrosol as precursor by hydrolysis precipitation method. The samples were characterized by XRD, TEM, BET, UV-Vis-DRS and FT-IR, respectively. The relation of the heat treatment temperatures and the photocatalysis activity of M-I₂-TiO₂ were also studied. The photocatalytic activity of samples was evaluated by degradation of methylene blue (MB) as target pollutant. The results show that the bimodal mesoporous structured M-I₂-TiO₂ exhibited stronger absorption in visible light region. The specific surface area of the bimodal mesoporous I₂-doped TiO₂ thermal treatment in air at 300 ℃ exceeded 227.6 m²/g, and that of the samples thermal treatment in air at 600 ℃ still have 111.8 m²/g, which indicated the samples have relative high thermal stability. The TiO₂/I₂ composite sample thermal treatment at 400 ℃ manifested the highest photocatalytic activity for photodecomposition of MB solution compared with thermal treatment at other temperatures, the uncomposite TiO₂ and Degussa P-25 under the irradiation of visible-light. Little difference of the activity was observed between the samples used for 6 times.