Preparation and structure analysis of titanium oxide nanotubes

Well crystallized nanoscale tubular materials have been synthesized via the reaction of TiO2 crystals of either anatase or rutile phase and NaOH aqueo us solution. The atomic structure of the synthesized tubular material is im aged by high-resolution transmission electron microscopy (HRTEM), and the c omposition of individual tubular structures is determined using selected ar ea energy dispersive X-ray spectroscopy (EDX). Our results show that the tu bular materials are well crystallized tubes with an average diameter of abo ut 9 nm and little dispersion, and are composed of mainly titanium and oxyg en. The atomic ratio of O/Ti is found, however, to vary from tube to tube. Detailed electron and x-ray diffraction studies show that the structure of our titanium oxide nanotubes do not agree with those made of TiO2 crystals with either anatase or rutile phase. HRTEM observations revealed that the t itanium oxide nanotubes usually have multiple shells, in analogy with multi walled carbon nanotubes, but the shell spacing is about 0.75 nm which is mu ch larger than that of the carbon nanotube, and the atomic structures of di fferent shells are well correlated. (C) 2001 American Institute of Physics.