Controlled synthesis of highly dispersed TiO 2 nanoparticles using SBA-15 as hard template

Abstract

Highly dispersed TiO 2 nanoparticles were successfully synthesized by a wet impregnation method using SBA-15 as hard template for confining the growth of TiO 2 nanocrystals, and then calcined at 550 °C in muffle furnace for 2 h. The as-synthesized samples were characterized with Fourier transform infrared spectra (FTIR), Raman spectroscopy, diffuse reflectance UV–visible spectroscopy (UV–vis), powder X-ray diffraction (XRD), small-angle X-ray diffraction (SAXRD), nitrogen adsorption, transmission electron microscopy (TEM) and photoluminescence spectra (PL). It was found that SBA-15 contained abundant silanol groups after removal of triblock copolymers by ethanol extraction and could easily adsorb a great number of titanium alkoxide via chemisorption. After subsequent hydrolysis of the anchored Ti complexes and calcination of the amorphous TiO 2, anatase TiO 2 nanocrystals with spherical shape and uniform particle diameter of about 6 nm were formed. A blue shift was observed in UV–vis absorption spectra due to the quantum size effect of TiO 2 nanoparticles. Moreover, the as-prepared TiO 2 nanoparticles showed a high PL intensity due to an increase in the recombination rate of photogenerated electrons and holes under UV light irradiation.