Sulfurized hematite for photo-Fenton catalysis

Abstract

A hematite/amorphous sulfur composite was prepared via simple heating hematite and α-sulfur in Teflon-lined autoclave at low temperature. The composite was characterized by X-ray diffraction (XRD), Raman spectrum, Thermal Gravity Analysis (TGA), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results revealed that an allotrope sulfur at 5–37% weight percent was found in the composite. After sulfuration, Sn2- or S22- was doped in the lattice of hematite, large amounts of OH and SO4 were adsorbed on the surface of hematite. Hematite/amorphous sulfur composite had superior photo-Fenton activities than pure hematite. This work also demonstrated that amorphous sulfur also had the activity of photo-Fenton catalysis. OH- and SO4 radicals facilitated dye adsorption and acted as a bridge to link H2O2. Moreover, SO4 radicals on hematite served as electron trapping center that can receive photo-induced electron from conduction band of hematite and transfer it to the adsorbed H2O2, increasing the rate of photo-Fenton reaction eventually.