Microwave-Assisted Hydrothermal Synthesis of Ag-Loaded Titania Nanotubes and Their Photocatalytic Performance

Ag-loaded titania nanotubes were synthesized by a microwave-assisted hydrothermal method and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS), and UV-visible (UV-Vis) diffuse reflectance spectroscopy. The titania nanotubes were found to be in the anatase phase after calcination. The length of the synthesized titania nanotubes was about 200 nm, the average outer diameter was 7-8 nm, the inner diameter was 5-6 nm and the specific surface area was found to be 371 m(2).g(-1).With Ag loading the silver atoms did not enter the lattices of the nanotubes but dispersed over the nanotube surface. Ag-loading had no effect on the nanostructure and the crystal phase of the TiO(2) nanotubes. The Ag-loaded titania nanotubes showed obvious visible light absorption and enhanced visible photocatalytic performance. The photocatalytic activity was evaluated by the photodegradation of a Rhodamine B aqueous solution under visible light. Compared with Ag-loaded P25 and pure titania nanotubes the Ag-loaded titania nanotubes enhanced the photoactivity and reached the maximum activity at a Ag/Ti molar ratio of 0.5%.