Synthesis of TiO_2 nanoparticles on mesoporous aluminosilicate Al-SBA-15 in supercritical CO_2 for photocatalytic decolorization of methylene blue

摘要

In the present study, titania nanoparticles were first constructed on mesoporous aluminosilicate Al-SBA-15 in supercritical carbon dioxide (Sc-CO_2) and the resultant samples were characterized by a combination of various techniques, such as X-ray diffraction (XRD), nitrogen physisorption, ~(27)Al 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-CO_2. As-synthesized TiO_2/Al-SBA-15 samples were evaluated in terms of photocatalytic decolorization of methylene blue in aqueous solutions. It was observed that all TiO_2/Al-SBA-15 samples showed satisfactory decolorization efficiency that was much higher than those of TiO_2/SBA-15 and commercial TiO_2 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.