Synthesis and photocatalysis of mesoporous anatase TiO 2 powders incorporated Ag nanoparticles

Abstract

Deposition of Ag nanoparticles on mesoporous anatase TiO 2 powders as well as on commercial TiO 2 powders via reduction of Ag + solution was performed and their photocatalytic activities were investigated. Photocatalytic activities of Ag/TiO 2 were evaluated by UV–vis test on degrading of methylene blue aqueous solution. For the synthesized mesoporous TiO 2 powders, the catalytic activity was found to be increased as the amount of Ag nanoparticles increased. However, for the commercial TiO 2 powders, the catalytic activity decreased as the amount of Ag increased. X-ray was employed to characterize the crystalline phase of synthesized Ag/TiO 2 powders. Particle sizes and morphologies of Ag/TiO 2 powders were investigated by transmission electron microscopy (TEM). Distribution of Ag in TiO 2 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 TiO 2 powders. However, the Ag nanoparticles retard the photocatalytic activity of commercial TiO 2 powders by shielding their effective surface area (only 7.0 m 2/g) for accessing light.