Synthesis and Structure Properties of Free-Standing TiO2 Nanotube Arrays

TiO2 nanotube arrays were made on the titanium foil by the method of anodic oxidation. Large-area crystallized free-standing TiO2 nanotube arrays were fabricated by a two-step anodization, and then crystallized by different heat-treatment processes. The morphology and structure of the TiO2 nanotube arrays were characterized by scanning electron microscope (SEM) and X-ray diffiaction (XRD). The results show that the diameter of the TiO2 nanotube at the voltage range of 50V similar to 65V was about 100nm. Anatase phase is the unique phase observed in free-standing TiO2 arrays annealed at the temperature of 400 degrees C similar to 610 degrees C. However, crystallographic orientation of anatase phase is influenced by the annealing temperature.