Larger Effect of Sintering Temperature Than Particle Size on the Photocatalytic Activity of Anatase TiO2

Abstract

Photocatalytic activity of anatase TiO2 that increases with the increase of its synthesis temperature has been widely reported, but the reason for that remains incompletely understood. In this work, the positive effect of synthesis temperature, presumably due to the growth of particle size, has been examined. Three series of anatase samples with various particle sizes were prepared from the hydrolysis of TiOSO4 in water at 150 °C, followed by calcinations in air. The particle size of TiO2, estimated by X-ray diffraction and N2 adsorption, increased with the increase of the hydrothermal time, calcination time, and calcination temperature. For phenol photodegradation in aerated aqueous suspension, three series of the catalysts showed different correlation between the activity and particle size of TiO2. However, with the same amount of Ag+ adsorbed on the oxide surface for phenol photodegradation in a N2-purged aqueous suspension, those catalysts showed activities all increasing with the particle size of TiO...