A study on the nanocrystalline titanium dioxide synthesized by ultrasonic-assisted sol-gel process

In this work, nanocrystalline titanium dioxide (TiO₂) powders doped with rare earth ion (Nd³⁺) were prepared by sol-gel process via ultrasonic irradiation. The frequency of ultrasonic was 20 kHz. The nanocrystalline powders were investigated by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), photoacoustic spectroscopy (PAS) which has been widely used to investigate the chemical and physical properties of many kinds of samples. For the special electronic structure of the rare earth ion, Nd³⁺ was used as a probe by photoacoustic spectroscopy to study the structural variation of the samples treated by ultrasonic irradiation during the sol-gel process. With the temperature of heat treatment increasing, the heat treatment(1-beta) of Nd³⁺ ion increases. As the temperature over 500degC, the nephelauxetic (1-beta) effect changes little.