Direct synthesis of nano titania on highly-ordered mesoporous SBA-15 framework for enhancing adsorption and photocatalytic activity

摘要

This paper reports the synthesis of TiO2-containing mesoporous catalysts for effectively enhancing the adsorption and photocatalytic activity. The factors that affect the photocatalytic activity of catalyst composites, including types of silica support, TiO2 content, calcination temperature, and catalyst mass, were examined in this study. The samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and surface area analysis. The experimental results showed that incorporating TiO2 nanoparticles into silica gel or SBA-15 frameworks could enhance the photodegradation rate more effectively than pure TiO2. The TiO2/SBA-15 sample displayed much higher adsorption and photocatalytic activity levels than did TiO2/silica-gel. The pore volume and pore size of TiO2/SBA-15 were as high as 1.317 cm(3)/g and 7.51 nm, respectively, which exceeded those of TiO2/silica-gel (0.437 cm(3)/g and 3.68 nm, respectively). The rate constants of photocatalysis were determined. The photodegradation rate of the catalyst increased with decreasing TiO2 content and increasing calcination temperature. The proposed method of preparing mesoporous photocatalysts is simple and suitable for mass production.