Electrodeposition preparation of Ag nanoparticles loaded TiO2 nanotube arrays with enhanced photocatalytic performance

Small silver (Ag) nanoparticles (NPs) loaded TiO2 nanotube arrays (TNAs) were prepared by a two-step method based on anodization method followed by an electrodeposited process. UV-visible diffuse reflectance spectroscopy (UV-vis) and photoluminescence emission spectroscopy (PL) demonstrated that the loaded Ag NPs significantly enhanced the light absorption of TiO2 nanotube arrays in the visible spectral range and improved the separation of photo-generated charge carriers. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) were also used for the characterization of surface morphology, elemental composition and microstructure of the pure TNAs and Ag NPs decorated TNAs. The results indicate that Ag NPs are uniformly distributed in the TNAs, the deposition process does not damage its ordered tubular structure and the loaded amounts and size of Ag NPs increase with the electrodeposition time. Moreover, the Ag NPs decorated TNAs largely enhanced the photocatalytic degradation of methyl orange (MO) under UV-visible light irradiation. Finally, A possible photocatalytic reaction mechanism of Ag NPs/TNAs has also been proposed.