热处理对TiO2纳米管结构相变的影响

TiO₂纳米管为无定形结构,焙烧后则由无定形转变为锐钛矿型,纳米管的管状结构被破坏,晶型转变是TiO₂纳米管的管状结构破坏的根本原因.经热处理,原来的TiO₂纳米管部分转变为长棒状的金红石型晶柱结构,而原料TiO₂在较大温度范围内焙烧均未出现长棒状晶柱结构;TiO₂由A→R的相变温差很大,TiO₂纳米管的A→R相变温度比原料约低350℃;合成的TiO₂纳米管的比表面积和孔体积很大.

Influence of Thermal Treatment on Structural Phase Transformation of TiO2 Nanotubes

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.