Preparation of Titania Nanotube Arrays by the Hydrothermal Method

TiO2 nanotube arrays were prepared by hydrothermal synthesis using ammonium hexafluorotitanate as deposition solution and anodic aluminum oxide attached to aluminum substrate as template. Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the as-prepared nanotube arrays, and the formation mechanism of the nanotube arrays was discussed. The results indicate that hydrothermal treatment time has an important influence on the formation of nanotube arrays with a homogenous morphology, and the optimum reaction time is 90 min under the experimental conditions. The titania nanotube arrays prepared by this method exhibit an especial morphology, that is, a continuous porous surface and discrete tubular cross-section structure. The formation of such an especial morphology is attributed to preferential deposition of the hydrolysis product on the surface of the template, which is caused by the different reaction rate when [TiF6]2− reacts with the surface and the cross-section of the template.