In situ templated synthesis of anatase single-crystal nanotube arrays

Anatase single-crystal nanotubes were obtained using an in situ templated method. First, highly ordered titania arrays were formed through an anodization process in H3PO4 electrolytes containing 0.5 wt% HF. Under optimized conditions titania nanotubes with a diameter of up to 100 nm and a length of up to 1.1 µm were prepared. Second, the crystallization and stability of the titania nanotubes were studied in air at elevated temperatures. Anatase single-crystal nanotubes were fabricated after annealing the sample in air at 450 °C. The anatase single-crystal structure was verified by selected area diffraction pattern and HRTEM images.