The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO₃/TiO₂Nanocomposites

Abstract

Series of WO 3 /TiO 2 nanocomposites were obtained by hydrothermal method followed by calcination in the temperature range from 400°C to 900°C. The characteristics of photocatalysts by X-ray diffractometry (XRD), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) showed that increasing the calcination temperature from 400 to 900°C resulted in change of photocatalytic activity under UV-Vis light. Moreover, the amount of WO 3 crystalline phase and amorphous phase in WO 3 /TiO 2 aggregates, as revealed by XRD analysis, was dependent on the calcination temperature. The WO 3 /TiO 2 samples with 8 mol% load of WO 3 in respect to TiO 2 calcinated at 500 and 800°C possess the highest photocatalytic activity in reaction of phenol degradation, which is about 1.2 and 1.5 times that with calcination at 400°C. The increase in calcination temperature above 400°C resulted in increase of WO 3 crystallinity and reduction of the amount of amorphous phase in the nanocomposite structure. Moreover, the annealing of nanocomposites above 700°C decreases the value of optical band gap energies of obtained WO 3 /TiO 2 nanomaterials.