Enhancement of Visible-Light-Induced Photocurrent and Photocatalytic Activity of V and N Codoped TiO₂Nanotube Array Films

Highly ordered TiO 2 nanotube arrays (TNAs) codoped with V and N were synthesized by electrochemical anodization in association with hydrothermal treatment. The samples were characterized by field emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The photocurrent and photocatalytic activity of codoped TiO 2 nanotube arrays were investigated under visible light irradiation. Moreover, the production of hydroxyl radicals (·OH) on the surface of visible light-irradiated samples is detected by a photoluminescence technique using terephthalic acid (TA) as a probe molecule. It was found that the V+N co-doped TiO 2 nanotube arrays showed remarkably enhanced photocurrent and photocatalytic activity than undoped sample due to the V and N codoping.