Synthesis of TiO2 supported on SBA-15 using chelating method and their photocatalytic decomposition of methylene blue.

SBA-15 mesoporous materials were successfully prepared by the conventional hydrothermal method and used as the support for TiO2 loaded SBA-15 photocatalysts. The synthesized materials were characterized by XRD, PL, FT-IR, BET and TEM. We also examined the activity of these materials as photocatalysts for the decomposition of methylene blue. The loading of titanium dioxide on the framework of SBA-15 makes the pore diameter and the pore volume decrease and decreases the surface area compared to that of SBA-15. For the TiO2 loaded SBA-15 photocatalysts, the IR absorption at approximately 960 cm(-1) is commonly accepted as the characteristic vibration of the Ti-O-Si bond. The PL peaks appears at about 410 nm at a loading ratio of less than 5% but moves to 430 nm at higher loading ratios. It was also shown that the excitonic PL signal is proportional to the photocatalytic activity for the decomposition of methylene blue. The photocatalytic activity increases with increasing TiO2 loading ratio, shows a maximum value at 7% TiO2/SBA-15, and then decreases at 10% TiO2/SBA-15.