采用溶胶-凝胶法将TiO2担载在介孔MCM-41分子筛上,制备了不同TiO2含量的系列TiO2/MCM-41复合材料,利用X射线衍射、N2吸附、紫外-可见光谱和透射电镜等方法对其进行表征.TiO2的晶型为锐钛矿相,复合材料的比表面积和孔体积随其中TiO2担载量(复合材料中TiO2与MCM-41的质量比)的增加而减小,TiO2的平均粒径随其担载量的增加而增大.以罗丹明B的光催化降解为探针反应,评价了TiO2/MCM-41复合材料的光催化降解活性.结果表明,在紫外光照射下,罗丹明B在该复合材料上的光催化降解反应遵循一级反应动力学,复合材料对罗丹明B的光催化降解活性明显高于商用TiO2(P-25),复合材料的光催化降解活性由复合材料的吸附能力和所含TiO2的光催化活性共同决定.
TiO2/MCM-41 composites with various titania content were prepared by loading titania into the mesopores of MCM-41 molecular sieves via the sol-gel method. TiO2/MCM-41 composites were characterized by X- ray diffraction(XRD), N2 adsorption, ultraviolet-visible (UV-Vis) absorption spectroscopy and transmission electron microscopy (TEM) techniques. The titania crystalline phase was anatase. The BET surface area and pore volume of the composites decreased with the increase of titania loading (mass ratio of TiO2 to MCM-41 in the composite). The average crystal size of these titania particles increased as the titania loading increased. The photocatalytic activities of TiO2/ MCM-41 composites were evaluated by the photocatalytic degradation of Rhodamine B. The degradation of Rhodamine B followed first-order reaction kinetics. The composites showed higher photocatalytic activities than P-25 commercial pure titania nanoparticles. The photocatalytic activities of the composites depended on their adsorption abilities and the activity of titania loaded into the MCM-41 molecular sieves.