The Effect of Calcination Temperature on Structure and Photocatalytic Properties of WO3/TiO2 Nanocomposites

Series of WO3/TiO2 nanocomposites were obtained by hydrothermal method followed by calcination in the temperature range from 400 degrees C to 900 degrees 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 degrees C resulted in change of photocatalytic activity under UV-Vis light. Moreover, the amount of WO3 crystalline phase and amorphous phase in WO3/TiO2 aggregates, as revealed by XRD analysis, was dependent on the calcination temperature. The WO3/TiO2 samples with 8 mol% load of WO3 in respect to TiO2 calcinated at 500 and 800 degrees 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 degrees C. The increase in calcination temperature above 400 degrees C resulted in increase of WO3 crystallinity and reduction of the amount of amorphous phase in the nanocomposite structure. Moreover, the annealing of nanocomposites above 700 degrees C decreases the value of optical band gap energies of obtained WO3/TiO2 nanomaterials.