Fe-doped TiO<sub>2</sub>/SiO<sub>2</sub> Aerogel Microspheres for Visible Light Photocatalysis Degradation of Methylene Blue

Abstract

In this paper, we present a strategy for the preparation of Fe-doped TiO2/SiO2 aerogel microspheres (Fe-TSAMs) for visible light photocatalysis degradation of methylene blue. A water- in-oil (W/O) emulsion of Span 80–Tween 85/n-heptane–n-butanol/FeCl3-doped TiO2/SiO2 alcoholic sols–formamide was obtained. Wet TiO2/SiO2 gel microspheres were prepared by the sol-gel process in the W/O emulsion, then they were dried at ambient pressure condition to prepare Fe-TSAMs. The Fe-TSAMs were characterized by N2 adsorption and desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the resultant Fe-TSAMs possess nanoporous network structure comprising TiO2 and SiO2 nanoparticles with diameters of 10-20 nm. The Fe-TSAMs have a mean diameter of about 100 μm, an apparent density of 0.26 g/cm3, a specific surface area of 360 m2/g, a pore volume of 1.77 cm3/g and the most probable pore size of 18.7 nm with the porosity of 87.7%. By using methylene blue as a simulated aqueous pollutant, the visible light photocatalysis properties of the Fe-TSAMs were investigated. The results indicate that low concentration Fe ion doping (5 wt%) could avoid the formation of recombination centers for photo-generated electron/hole pairs. Compared with commercial P25 TiO2 powders, Fe-TSAMs exhibit excellent photocatalytic ability for degradation of methylene blue under visible light region. The Fe-TSAMs could be reclaimed conveniently and the reused Fe-TSAMs also have a good photocatalytic activity.