Study On Prearation Of TiO₂ Nanotube Arrays And Photocatalytic Activity

The unique physical chemistry properties of TiO₂ nanotube films derived from high surface-to-volume ratios and specific architectures, making them of great applicable potential in the fields of photocatalysis, gas sensing, photoelectrolysis, and photovoltaics.In this paper, the TiO₂ nanotube arrays were prepared by electrochemical anodization of titanium foils in electrolyte with EG(polyethylene glycol, reference). We have concentrated on the factors affected on the growth of titania nanotube arrays, such as the anodization duration, the anodization times, and heat treatment temperature. The experiments showed that TiO₂ nanotube arrays prepared with pre-treatment kept better morphology structure. The effect of heat treatment on the nanotube morphology structure showed that the nanotube arrays annealed at 400℃and 450℃displayed well morphology structure, while the nanotube arrays annealed at 550℃collapsed badly and the morphology structure could not be kept. TiO₂ nanotube arrays were calcined with different tempature, the XRD spectra showed that the crystal type of TiO₂ nanotube arrays would be transformed from anatase to rutile as the calcining temperature increased. Followingly, the FE-SEM micrographs of TiO₂ nanotube arrays anodized for 1, 2, 3, and 4h showed that the nanotube become longer with time increasing; meanwhile, the nanotube antase crystalline of TiO₂ annealed at 450℃had reached to perfect according to the XRD spectra.In this paper, degrading methylene blue(MB) and Rhodamine B(Rh.B) under different condition. TiO₂ nanotube arrays with different heat treatment temperature were used in resorption-desorption process and photocatalytic reaction. The results demonstrated that the nanotubes resorption ability for MB increased with heat temperature and the same-length nanotubes annealed at 450℃manifested the optimal performance, was up to 77.42%. Followingly, TiO₂ nanotube arrays with 1⁴h anodic time were exprimented in photocatalytic reaction. The results manifested that photocatalytic activity of TiO₂ nanotube arrays was very excellent, especially annealing temperature of TiO₂ nanotube arrays was 450℃, was up to 91.50%. The study on dynamics of photocatalytic degradation for Rhodamine B indicated that it was all in agreement with one order dynamics model when TiO₂ nanotubes used as photocatalysts, and the maximal reaction rate constant(k=0.0314min-1) was corresponding to the nanotubes with anodic time 2h.