Preparation and characterization of TiO2 photocatalysts by Fe3+ doping together with Au deposition for the degradation of organic pollutants

Abstract

Fe3+ doped TiO2 deposited with Au (Au/Fe–TiO2) was successfully prepared with an attempt to extend light absorption of TiO2 into the visible region and reduce the rapid recombination of electrons and holes. The samples were characterized by X-ray diffraction (XRD), N2 physical adsorption, Raman spectroscopy, atomic absorption flame emission spectroscopy (AAS), UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectra. The photocatalytic activities of the samples were evaluated for the degradation of 2,4-chlorophenol in aqueous solutions under visible light (λ>420nm) and UV light irradiation. The results of XRD, XPS and high-resolution transmission electron microscopy (HRTEM) analysis indicated that Fe3+ substituted for Ti4+ in the lattice of TiO2, Au existed as Au0 on the surface of the photocatalyst and the mean particle size of Au was 8nm. Diffuse reflectance measurements showed an extension of light absorption into the visible region for Au/Fe–TiO2, and PL analysis indicated that the electron–hole recombination rate has been effectively inhibited when Au deposited on the surface of Fe-doped TiO2. Compared with Fe doped TiO2 sample and Au deposited TiO2 sample, the Au/Fe–TiO2 photocatalyst exhibited excellent visible light and UV light activity and the synergistic effects of Fe3+ and Au was responsible for improving the photocatalytic activity.