Effects of Sr2+, Fe3+ and Al3+ doping on the properties of TiO2 prepared using the sol–gel method

Abstract

The present study aims to synthesize highly active and transparent monoliths of Al-, Fe- and Sr-doped TiO 2 . These photocatalysts were synthesized for the first time using a simple modified solgel process. Titanium isopropoxide was used as a precursor of titanium. The control of hydrolysis and polycondensation of the precursor were mediated by the esterification reaction between acetic acid and the solvent at room temperature. The doped monoliths prepared by this method were transparent at wavelengths ranging from 500 nm to 800 nm. The noncalcinated Al–TiO 2 and Fe–TiO 2 crystallized in the anatase form. Powder X-ray diffraction confirmed the amorphous-to-anatase and the anatase brookite to-rutile phase transformations at different treatment temperatures. Based on the obtained results, only the anatase form was observed in all samples calcined at 450 °C. According to the N 2 adsorption/desorption analysis, transparent gels had a larger surface area and high porosity. Al–TiO 2 showed improved photocatalytic performance in the photodegradation of methylene blue (MB) upon UV irradiation. Fe–TiO 2 exhibited a good yield for the degradation of MB upon solar irradiation. This study uses transparent monoliths as a novel approach to achieve the required findings.