Effect of Calcination Temperature on Crystal Structure and Photocatalytic Prop- erty of TiO2/Diatomite Nanoparticles

TiO2/diatomite photocatalysts were synthesized by a facile Sol-Gel method using diatomite as supporter and tetrabutyl titanate (TBOT) as precursor. The crystalline and morphological properties of catalysts with different calcination temperatures were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and UV-Vis spectroscopy. Results reveal that the crystallite size becomes larger and the anatase phase transforms to the rutile phase at elevated temperature. Compared with unimmobilized TiO2, the diatomite supporter impedes the transformation and prevents nano-TiO2 particles from aggregation. The effect of calcination temperature on photocatalytic reactivities of these catalysts was investigated by UV-assisted degradation of 10 mg/L Rhodamine B (RhB). The sample calcined at 750℃ exhibits significantly enhanced reactivity with the removal rate of RhB up to about 100% after irradiation for 120 min, equivalent to that of Degussa P25 under similar conditions. The highest photocatalytic activity is observed in TiO2/diatomite calcined under 750℃ which can be attributed to the presence of anatase and rutile phases in an appropriate ratio at 9:1.