Analysis of silver particles incorporated on TiO2 coatings for the photodecomposition of o-cresol

Abstract Silver-modified TiO 2 (Ag–TiO 2 ) and pure TiO 2 coatings were prepared on sapphire substrates by dip-coating process for the photodecomposition of o-cresol. In order to investigate the behaviors of silver incorporated on TiO 2 surface coatings, Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), diffuse reflectance UV–Vis spectra (DRS), and photoluminescence (PL) emission spectra were performed. Experimental results indicate that the silver on TiO 2 surface coatings were easily oxidized into silver oxide (Ag 2 O), because of the existence of Ag 2 O crystal phase in XRD spectrum and Ag 2+ –O and O 1s –Ag chemical bonding states in Ag 3d and O 1s narrow scans of XPS, respectively. PL spectra showed that as increasing the amount of silver incorporated, the PL intensity of Ag–TiO 2 coatings evidently decrease, which means that the Ag–TiO 2 coatings have higher efficiencies of charge carrier trapping, immigration and transferring, and subsequently promote the photodecomposition rate constants after the UV/TiO 2 process. An optimal composition of 0.50 wt.% Ag–TiO 2 coating for the photodecomposition of o-cresol correspond to a maximum photodecomposition rate constant (k value) of 0.01 min − 1 as compared to that of the pure TiO 2 coatings ( k = 0.0062 min − 1 ).