Synthesis and characterization of Fe3O4/BiOI n-p heterojunction magnetic photocatalysts

The visible-light-driven Fe3O4/BiOI n-p heterojunction photocatalysts were successfully synthesized by a facile and economical solve-thermal method. The as-prepared samples were systematically characterized by X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectra, and vibrating sample magnetometer. The methyl orange and sulfadiazine sodium salt were taken as the model pollutants to estimate the photocatalytic activities of the Fe3O4/BiOI composites with different Fe3O4 contents. The results revealed that the photocatalytic properties of photocatalysts within the appropriate loading range were superior to pure BiOI. Among them 7 wt% Fe3O4/BiOI composite exhibited the highest photocatalytic activity both on degradation of MO and SD-Na. The increase in photodegradation activity may be attributed to the moderate loading of Fe3O4, which could promote the separation of electron-hole pairs effectively. Furthermore, the introducing of Fe3O4 provides the composite a good magnetic property, which greatly promotes the practical application of Fe3O4/BiOI composite photocatalysts in water purification.