Ti-containing mesoporous silica for methylene blue photodegradation

Photodegradation of methylene blue (MB) on Ti-containing mesoporous silica prepared by microwave-assisted irradiation as a function of Si/Ti molar ratio was studied. The materials were characterized by N(2) adsorption, XRD, UV-vis/DR, and TEM. All solids showed mesoporous textures with high surface areas, relatively small pore size diameters and large pore volume. XRD showed that framework of solids consists of amorphous silica. It was found that the lower the Si/Ti ratio the higher the photocatalytic activity. Under irradiation with a lamp with more photons from visible light the sample with a Si/Ti ratio equal to 10 showed a higher photoactivity than that of a commercial TiO(2) photocatalyst. This result was in agreement with the UV-vis/DR spectra which showed that material with a Si/Ti = 10 has slightly higher energy band gap than that of commercial TiO(2) suggesting that these materials behave as a photoactive semiconductor. (C) 2010 Elsevier B.V. All rights reserved.