Preparation of highly dispersed TiO2 in hydrophobic mesopores by simultaneous grafting and fluorinating

TiO2 photocatalysts highly dispersed in the MCM-41 mesoporous silica material were synthesized using two different TiO2 precursors of TiF4 and (NH4)2TiO(C2O4)2. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), UV–vis absorption, X-ray photoelectron spectroscopy (XPS), and Ti K-edge X-ray absorption fine structure (XAFS). The hydrophobic properties and catalytic activities of photocatalysts with different TiO2 precursors and loading amount were examined by adsorption and degradation of iso-butanol diluted in water. The results showed that the TiO2 loaded MCM-41 prepared from TiF4 exhibited higher photocatalytic activity than from (NH4)2TiO(C2O4)2. The fluorine-modified hydrophobic pore walls formed in the impregnation process using TiF4 as well as highly dispersed TiO2 nanoparticles play a crucial role for the high photocatalytic efficiency.