A core–shell structured magnetic Ag/AgBr@Fe2O3 composite with enhanced photocatalytic activity for organic pollutant degradation and antibacterium

Abstract

A core–shell structured magnetic Ag/AgBr@Fe₂O₃ composite was synthesized through a facile solvothermal method. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible absorption spectroscopy (UV-vis) were applied to characterize the structures and properties of the as-prepared samples. The results indicate that Fe₂O₃ was coated on the surface of Ag/AgBr and heterostructures were formed. Electrochemistry analysis and photoluminescence (PL) spectra analysis indicate that the introduction of Fe₂O₃ could improve electron and hole separation efficiency. The photocatalytic activity of the Ag/AgBr@Fe₂O₃ composites was evaluated by using organic dye methyl orange (MO), endocrine disrupting chemical bisphenol A (BPA) and Escherichia coli (E. coli) as the target pollutants. The as-prepared Ag/AgBr@Fe₂O₃ composites exhibited much higher photocatalytic activities than pure Ag/AgBr, which was attributed to the effective charge separation of the Ag/AgBr@Fe₂O₃ composite. In addition, the as-prepared Ag/AgBr@Fe₂O₃ composite has magnetic properties, therefore after the photocatalytic reaction, it can be quickly separated from solution by an extra magnetic field. Trapping experiments and ESR analysis indicate that the h⁺ and ˙O₂⁻ are the main active species for the photocatalytic degradation. A possible Z-scheme pathway photocatalytic mechanism was proposed.