Sulfurized hematite for photo-Fenton catalysis

A hematite/amorphous sulfur composite was prepared via simple heating hematite and a-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, S-n(2-) or S-2(2-) 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.