One-pot Synthesis and Photocatalysis of Encapsulated TiO_2 in Mesoporous SiO_2

摘要

Nano TiO_2 particles encapsulated in mesoporous SiO_2 materials (abbreviated as TiO_2/MS) were prepared by incorporating the nano-sized TiO_2 particles in the pore-directing micelles during the cooperative assembly of silica precursor and surfactant. The materials were characterized with X-ray powder diffraction (XRD), transmission and scanning electron microcopies (TEM and SEM), N_2 sorption, ICP-MS and UV-Vis spectroscopy. XRD patterns showed that titania was in the anatase phase. The results of TEM and N_2 sorption studies confirmed the deposition of nano-sized particles inside the mesopores of silica material without destroying their integrity. UV-Vis spectra showed blue shift of the absorption edge for TiO_2/MS relative to bulk anatase. When used as photocatalysts, TiO_2/MS showed similar activity as anatase TiO_2 in photo-degradation of phenol. However, lower activity than anatase TiO_2 was observed in photo-degradation of lipase, implying that most of the nano-sized TiO_2 were encapsulated inside the mesopores of silica.