Synthesis and photocatalysis of mesoporous anatase TiO2 powders incorporated Ag nanoparticles

Deposition of Ag nanoparticles on mesoporous anatase TiO2 powders as well as on commercial TiO2 powders via reduction of Ag+ solution was performed and their photocatalytic activities were investigated. Photocatalytic activities of Ag/TiO2 were evaluated by UV-vis test on degrading of methylene blue aqueous solution. For the synthesized mesoporous TiO2 powders, the catalytic activity was found to be increased as the amount of Ag nanoparticles increased. However, for the commercial TiO2 powders, the catalytic activity decreased as the amount of Ag increased. X-ray was employed to characterize the crystalline phase of synthesized Ag/TiO2 powders. Particle sizes and morphologies of Ag/TiO2 powders were investigated by transmission electron microscopy (TEM). Distribution of Ag in TiO2 powders was revealed by element mapping under element dispersive X-ray analysis (EDAX). It is inferred that the Ag nanoparticles reduce the recombination of electron-hole pairs and therefore enhance the photocatalytic activity of the synthesized mesoporous TiO2 powders. However, the Ag nanoparticles retard the photocatalytic activity of commercial TiO2 powders by shielding their effective surface area (only 7.0 m2/g) for accessing light.