Structure transition of nano-titania during calcination

Abstract

In order to study the structure transition during calcination, nano-titania powders prepared by hydrolyzing precipitation approach and calcined at 300, 400, 500, 600 and 700 °C were characterized by XRD, TEM and electron diffraction (ED), respectively. The results show that titania powders calcined below 500 °C are almost composed of anatase, rutile appears below 500 °C and its ratio increases gradually with increase of calcin temperature; nano-titania particles are smaller than 40 nm mostly and the dispersion is related to calcining temperature; the interplanar distances of nano-anatase single crystalline change gradually when calcing temperature increases to 500 °C; so do that of nano-rutile single crystalline when calcining temperature charges from 600 to 700 °C. The conclusions can be drawn that the temperature of transformation from anatase to rutile is below 500 °C and the process carries on gradually. Both inter-planar distances and the structure of nano-titania transform gradually with increasing calcing temperature.

Keywords

nano-titania / phase transformation / structure transition / inter-planar distances

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