Effects of Calcination Time on Structure and Morphology of Porous TiO2-Al2O3 Material

Porous TiO2-Al2O3 composites were prepared through sol-gel method after calcination at 500 degrees C for different time. PEG 1000 was used as a template and tetrabutyl titanate and aluminum isopropoxide were used as the precursors. The materials prepared under different calcination temperatures were all composed of anatase TiO2 and amorphous Al2O3. All the samples presented anatase TiO2 crystalline structure. There was no rutile TiO2 phase appearing in the patterns. Meanwhile, there were no noticeable diffraction peaks of any of crystalline phases of Al2O3. Calculated from Scherrer formula on (101) plane of the XRD patterns, crystallite sizes of anatase TiO2 were 10.06 nm, 10.55 nm, and 11.13 nm, respectively. The surfaces of the materials were very rough with long grooves on the surface. The materials were composed of large amorphous like matrix, along with some small particles laying on the surface.