Enhanced photocatalytic activity of magnetic core–shell Fe3O4@Bi2O3–RGO heterojunctions for quinolone antibiotics degradation under visible light

Abstract

A magnetically separable Fe3O4@Bi2O3–RGO core–shell heterostructured photocatalyst was successfully prepared through a self-assembly method for the first time. The Fe3O4 nanoparticles with an average diameter of 200 nm was wrapped by approximately 50 nm thick layer of Bi2O3 to form unique Fe3O4@Bi2O3 nanospheres, then loaded on the surface of reduced graphene oxide (RGO). Compared with pure Bi2O3 and Fe3O4@Bi2O3, the as-synthesized Fe3O4@Bi2O3–RGO nanocomposites showed broadened visible light adsorption range, increased charge separation efficiency, excellent photocatalytic activity and cyclic stability for degradation of quinolone antibiotics (QAs) under visible light irradation. The degradation rate of ciprofloxacin (CIP) with Fe3O4@Bi2O3–RGO photocatalyst could reach 98.3% in 240 min and it was still above 80% after ten photocatalytic reaction cycles. More importantly, benefiting from the introduction of Fe3O4 and RGO, the Fe3O4@Bi2O3–RGO nanocomposites could effectively prevent the rapid recombination of photogenerated electron–hole pairs and photocorrosion phenomenon of Bi2O3, which made it become a highly stable and durable photocatalyst. These attractive features make the Fe3O4@Bi2O3–RGO nanocomposites to be a promising photocatalyst for visible light photocatalytic degradation of QAs in water pollutants treatment.