S-doped α-Fe2O3 as a highly active heterogeneous Fenton-like catalyst towards the degradation of acid orange 7 and phenol

S-doped alpha-Fe2O3 (alpha-Fe2O3/S) was synthesized with ferrous sulfate and Na2S2O3 via a hybrid hydrothermal-calcination treatment. The crystal phase, special surface area, morphology of the alpha-Fe2O3/S as well as the chemical state of the sulfur were studied by X-ray diffraction (XRD), scanning electro microscopy (SEM), Raman spectrum and X-ray photoelectron spectroscopy (XPS). The Fenton and photo-Fenton reactivities of the alpha-Fe2O3/S were tested by degrading acid orange 7 (AO7) and phenol. Although alpha-Fe2O3/S showed little Fenton reactivity in the dark, it had an excellent heterogeneous Fenton reaction under. either UV or visible irradiation, while other alpha-Fe(2)O(3)s were still kept inactive. S element was found to dope into alpha-Fe2O3 in the forms of FeS or FeS2 in alpha-Fe2O3/S. The doped S element promotes the photo-Fenton reaction of alpha-Fe2O3/S via two roles: retarding the recombination of photogenerated charge carriers and promoting the electron transfer between the peroxide species and iron ions at the interface. (c) 2010 Elsevier B.V. All rights reserved.