Abstract: Nanosized TiO₂ has excellent photocatalytic activity to degrade most of pollutants.The most important focus has been on the improvement of photocatalytic activity and the efficiency of utilizing solar energy. The researches has proved that nonmetal-doping can activate its visible-light activity.Self-organized F-doped TiO₂ nanotube arrays were fabricated by a one-step electrochemical anodization process on a Ti sheet. The prepared samples were annealed in air and detected by SEM, XRD and XPS. SEM images The results show that the well ordered TiO₂ nanotube arrays with the average tube diameter of 40 nm and the average tube length of 700 nm are successfully fabricated. The substitutional F atoms that occupied oxygen sites in the TiO ₂ crystal lattice cause the appearance of active spices Ti³⁺ , as evidenced by from XPS. The sample annealed at 673 K exhibits the highest photocurrent intensities under visible light irradiation, w hich may be attributed to the Ti³⁺ .The removal efficiency reaches 37.2% of AO7 at 180 min and the photoelectrocatalytic synergetic factor is 1.33. DFT study calculations suggests s that the valence and conduction band of F-TiO₂ consist of the electrons of O2 p and Ti 3 d, while the small amount of electrons of F 2 p do not change the band gap of TiO₂.

Key words: TiO₂ nanotube arrays, F doped, Visible visible light, Electronic electronic Structures structures