Platinum-incorporated TiO 2 (Pt-TiO 2) and silver-incorporated TiO 2 (Ag-TiO 2) coatings on sapphire tubes of a thin-film photoreactor were prepared using a photoreduction process. Results of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) revealed that the Ag-TiO 2 coatings consisted of a mixture of Ag 2O, Ag and TiO 2 particles, owing to the partial oxidization of silver particles on the TiO 2 coatings, while the Pt-TiO 2 coating contained a mixture of Pt and TiO 2 particles. Diffuse reflectance UV-Vis spectra (DRS) showed that metal particles (Ag or Pt) incorporated into the TiO 2 coatings promoted optical absorption in the visible region and made it possible for the coatings to be excited by visible light. Photoluminescence (PL) spectra showed that the PL intensity of the Pt-TiO 2 coating was lower than that of the Ag-TiO 2 and TiO 2 coatings, indicating that the Pt-TiO 2 coating had a higher efficiency of charge carrier trapping, immigration and transfer, which subsequently promoted the pseudo-first-order rate constants after the UV/TiO 2 process. The Pt-TiO 2 coatings for the photocatalytic decomposition of o-cresol under UV light irradiation corresponded to a higher pseudo-first-order rate constant (k) of 0.02min 1 when compared with the photocatalytic decomposition rates of pure TiO 2 coatings (k=0.0062min 1) and Ag-TiO 2 coatings (k=0.01min 1). The experimental results also indicated that the photodegradation rate of the Pt-TiO 2 coating under visible light irradiation was significantly higher than the photodegradation rates of the Ag-TiO 2 and pure TiO 2 coatings.
- visible light
ASJC Scopus subject areas
- Environmental Chemistry
- Waste Management and Disposal
- Water Science and Technology