Magnetically recyclable Fe3O4@SiO2/Bi2WO6/Bi2S3 with visible-light driven photocatalytic oxidative desulfurization

Novel core-shell structural magnetic Fe3O4@SiO2/Bi2WO6 (F-BWO) was obtained by a multistep process. Bi2S3 Quantum Dots (QDs) with the size of about 5 nm were deposited on the surface of Bi2WO6 shell to obtain Fe3O4@SiO2/Bi2WO6/Bi2S3 (F-BWO-BS) heterostructures. The experimental results indicated that F-BWO-BS exhibits the enhanced fuel oil photocatalytic-oxidative-desulfurization (Photo-Cat-ODS) and RhB photocatalytic degradation activity than that of F-BWO. The as-prepared F-BWO-BS-2 exhibited the best activity, the rate constant (k(app)/min(-1)) for RhB photocatalytic degradation is approximately 1.5 times higher than that of F-BWO. Furthermore, the F-BWO-BS-2 exhibited the best Photo-Cat-ODS activity, the desulfurization rate could reach 100% after illumination for 1.5 h. The enhanced photocatalytic activity of F-BWO-BS can be attributed to the synergistic effect of magnetic Fe3O4@SiO2 support - core, Bi2WO6 - shell and Bi2S3 QDs. The experimental result also revealed that magnetic F-BWO-BS photocatalyst is easily magnetically separated with good stability and recyclability.