The Effects of Calcination Conditions on the Properties of TiO2-Al2O3 Composite Materials

Wenjie      Zhang; Xiaofang      Han; Ruyuan      Li; Hong      Li

doi:10.2174/22106812112029990004

Abstract

TiO₂-Al₂O₃ composite material was prepared by a sol-gel method using a sol mixture derived from tetrabutyl titanate and aluminium isopropoxide. Crystalline structure, surface morphology, composition, BET surface area, and pore size distribution of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Xray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and N₂-adsoption and desorption. The composite materials are composed of anatase TiO2 and amorphous Al2O3. There is no apparent difference in surface morphology among the samples calcinated at different temperature. Titanium is in its full oxidation state and there is no reduced titanium state existing in TiO₂-Al₂O₃ composite. The existence of Al2O3 causes binding energies shift to higher energy end for Ti₂p₃/₂, Ti₂p₁/₂, and O1s levels. Specific surface area of the composite samples decreases and TiO₂ crystallite size increases with increasing calcination temperature. The TiO₂-Al₂O₃ composite sample calcinated at 500 °C for 3 h shows both the maximum adsorption capacity and photocatalytic activity. Nearly all of the initial methyl orange is removed from TiO₂-Al₂O₃ composite after a certain time period. As compared with pure TiO₂, photocatalytic activity and adsorption capacity of TiO₂-Al₂O₃ composite are enhanced obviously.