Enhanced Photocatalytic Properties of Ag-Loaded N-Doped Tio2 Nanotube Arrays

Highly ordered TiO nanotube (TiO NT) arrays were prepared by anodic oxidizing method on the surface of the Ti substrate. Nitrogen-doped TiO nanotube (N-TiO NT) arrays were carried out by ammonia solution immersion, and Ag nanoparticles loaded N-doped TiO nanotube (Ag/N-TiO NT) arrays were obtained by successive ionic layer adsorption and reaction (SILAR) technique. The samples were characterized by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) emission spectra, ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy (DRS). The result indicated that the diameter and wall thickness of the TiO NT are 100–120 and 20–30 nm, respectively. Moreover, the morphology and structure of the highly ordered TiO NTs were not affected by N-doping. Furthermore, Ag nanoparticles were evenly deposited on the surface of TiO NTs in the form of elemental silver. Finally, the photocatalytic activity of Ag/N-TiO NTs was evaluated by degradation of methyl orange (MO) under visible-light irradiation. The Ag/N-TiO NTs exhibited enhanced photocatalytic properties, which could reach 95% after 90-min irradiation.