α-Fe2O3/BiFeO3 composites as visible-active photocatalysts and their optical response mechanism

Abstract

α-Fe2O3/BiFeO3(BFO) composites have been prepared by loading α-Fe2O3 onto the surface of BFO via a two-step hydrothermal method. The composites have been systematically investigated by X-ray diffraction (XRD) technique, field emission scanning electron microscopy, energy dispersive spectrometer, UV–vis spectra and X-ray photoemission spectroscopy (XPS). It is observed that all of α-Fe2O3, BFO and α-Fe2O3/BFO composites show a very high purity as detected by XRD. The band gap energies of composites calculated by the UV–visible spectra are smaller than those of both α-Fe2O3 and BFO, which enhances the visible light absorption capability. The photocatalytic degradation of Rhodamine B under visible light irradiation showed that the efficiency of α-Fe2O3/BFO composite could be enhanced than that of both α-Fe2O3 and BFO. The photocatalytic reaction mechanism of the composites was analyzed based on the position of energy bands as characterized by XPS measurement.