Abstract: TiO₂nanotubes can only exist in the amorphous state, and the tubulous structure of TiO₂nanotubes is destroyed when the crystalline phase of TiO₂calcined transforms from amorphous phase into anatase phase.The crystalline phase transformation is the fundamental reason why the tubulous phase strueture is destroyed.It was also found that the long-bar shape crystal columns in rutile were formed when TiO₂nanotubes were calcined at 700-800 ℃, but the same case didn′t occur to the raw material how high no matter the temperature for calcining was.The temperatures of phase transformation of TiO₂nanotubes from anatase to rutile is lower than that of the raw material calcined at about 350℃. TiO₂nanotubes have a very large specific surface area and pole volume.

Key words: TiO₂nanotube, Inorganic functional material, Structure phase transformation, Calcination