Enhanced visible-light-active photocatalytic performances on Ag nanoparticles sensitized TiO2 nanotube arrays

TiO2 nanotube arrays (TNAs) synthesized using anodic oxidation method perform an excellent photocatalytic activity due to their unique tubular structure and large specific surface areas. Here, we reported a modified hybrid TiO2 nanostructure, Ag nanoparticles sensitized TiO2 nanotube arrays (Ag@TNAs), which were synthesized using classical anodic oxidation methods and special hydrothermal methods. Field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) showed Ag nanoparticles were well-dispersed and anchored to the top surface of TNAs. X-Ray diffraction (XRD) showed the phases of anatase TiO2, silver and Ti substrate obviously. UV-vis absorption spectra performed an enhanced absorbance to visible light and photoluminescence (PL) performed a better optical property than pure TNAs. The photocatalytic performances of the as-synthesized Ag@TNAs were evaluated in terms of their photodegradation rate of methylene blue (MB) in an aqueous solution under light. The Ag@TNAs showed an enhanced photocatalytic activity compared with pure TNAs, and a probable photocatalytic mechanism was proposed.