Synthesis of TiO2 nanoparticles on mesoporous aluminosilicate Al-SBA-15 in supercritical CO2 for photocatalytic decolorization of methylene blue

In the present study, titania nanoparticles were first constructed on mesoporous aluminosilicate Al-SBA-15 in supercritical carbon dioxide (Sc-CO2) and the resultant samples were characterized by a combination of Various techniques, such as X-ray diffraction (XRD), nitrogen physisorption, Al-27 MAS NMR, UV-vis diffuse reflectance spectroscopy, and transmission electron microscopy (TEM). It was identified that the Al species incorporated samples retained structures similar to that of the parent SBA-15. In addition, the content of titania loading varied with reaction temperature and time in Sc-CO2. As-synthesized TiO2/Al-SBA-15 samples were evaluated in terms of photocatalytic decolorization of methylene blue in aqueous solutions. It was observed that all TiO2/Al-SBA-15 samples showed satisfactory decolorization efficiency that was much higher than those of TiO2/SBA-15 and commercial TiO2 under identical conditions, which could be mainly attributed to the effective adsorption capability, resulting from the extension of specific surface area after substitution of Si species with Al species. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.