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

Abstract

Series of WO3/TiO2nanocomposites 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 WO3crystalline phase and amorphous phase in WO3/TiO2aggregates, as revealed by XRD analysis, was dependent on the calcination temperature. The WO3/TiO2samples with 8 mol% load of WO3in respect to TiO2calcinated 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 WO3crystallinity 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 WO3/TiO2nanomaterials.

Visible Light Photodegradation of Formaldehyde over TiO2 Nanotubes Synthesized via Electrochemical Anodization of Titanium Foil

“…These wavelengths (nm) were converted to energy (eV) according to Pishkar et al [53] and the values are given in Table 1. From the inspection of Table 1, it appears that the bandgap gap energy decreased with increasing calcination temperature and the results are consistent with the results reported by Mioduska et al [54] that the calcination temperature can influence the energy bandgap. It is suggested that the increase in temperature can cause an incremental increase in the absorption coefficient due to the increase of defects sites.…”

Photocatalytical Degradation of Toluene and Cyclohexane Using LED Illumination

“…Next, it was centrifuged, dried, and calcined at 400ºC or 800ºC. A more detailed account of this procedure can be found elsewhere [18]. The samples were chosen based on earlier data regarding process parameters and characterization of photocatalysts done by Mioduska et al [18].…”

“…A more detailed account of this procedure can be found elsewhere [18]. The samples were chosen based on earlier data regarding process parameters and characterization of photocatalysts done by Mioduska et al [18]. In the cited paper, although pertaining to the aqueous phase, photocatalysts calcined at 800ºC were characterized with enhanced photodegradation efficiency compared with those calcined at lower temperatures.…”

Effect of Thermal Treatment on the Phase Composition and Surface Properties of WO3‐TiO2 Nanocomposites Synthesized via Hydro‐Thermal Method

“…Several methods have been developed and effectively used for improving and shifting the sensitivity of TiO 2 to visible light (λ>400 nm). Doping of metals into the semi‐conductors like TiO 2 can reduce the band gap by introducing strain and defect states in them [10–12] …”