title: Synthesis of nano titania particles embedded in mesoporous SBA-15: characterization and photocatalytic activity.
abstract: Supported nanocrystalline titanium dioxide (TiO2) has been prepared by a post-synthesis step via Ti-alkoxide hydrolysis through the use of mesoporous SBA-15 silica. TiO2/SBA-15 composites with various TiO2 loading have been prepared and characterized by X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy and diffusive reflective UV-vis spectroscopy. The addition of mesoporous SBA-15 prevents the anatase to rutile phase transformation and the growth of crystal grain. TiO2 did not block the SBA-15 pores, and their surface was fully accessible for nitrogen adsorption. Calcination in air of the composites up to 800 degrees C did not change the nanocrystal phase and slightly increased the domain size from 5.0 to 7.5 nm, indicating that the anatase TiO2 grains in the mesostructures have a relatively high thermal stability and proper pore diameter allows controlling the size of obtained titania particles. The TiO2/SBA-15 composites prepared by this study showed much higher photodegradation ability for methylene blue (MB) than commercial pure TiO2 nanoparticles P-25. Experimental results indicate that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of composite and the photocatalytic activity of the titania, and there is an optimal ratio of Ti:Si, too high or low Ti:Si ratio will lower the photodegradation ability of the composites.
authors.affiliation: Department of Chemistry, Jinan University, Guangzhou 510632, People's Republic China. tyangj@jnu.edu.cn
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Liwei
authors.initials: L
authors.lastname: Zhu
authors.forename: Shaoyuan
authors.initials: S
authors.lastname: Chen
authors.forename: Yuanming
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Tang
authors.forename: Yulei
authors.initials: Y
authors.lastname: Zhu
authors.forename: Yongwang
authors.initials: Y
authors.lastname: Li
mesh_terms: D002384:Catalysis; D008027:Light; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D012822:Silicon Dioxide; D014025:Titanium / Q000737:chemistry*
chemical_list: C509969:SBA-15; C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium