Effective Visible Light-Driven Photocatalytic Degradation of Ciprofloxacin over Flower-like Fe3O4/Bi2WO6 Composites

Photocatalytic degradation of organic pollution is a vital path to deal with environmental problems. Here, a direct Z-scheme 2D/2D heterojunction of a Fe₃O₄/Bi₂WO₆ photocatalyst is fabricated for the degradation of ciprofloxacin by a self-assembly strategy. Furthermore, to characterize the morphology of the obtained composite photocatalysts, various kinds of characterization methods were employed like XRD, XPS, SEM, and TEM. It is indicated that the flower-like photocatalyst is composed of nanosheets. Comparable photocatalysts were prepared by controlling the hydrothermal temperature and the iron content. In the photocatalytic degradation of ciprofloxacin (CIP) in water, under visible light irradiation, FB-180 (synthesized at 180 °C with 4% iron content) presents approximately 99.7% degradation efficiency in only 15 min. Meanwhile, during photocatalytic degradation reactions, the Fe₃O₄/Bi₂WO₆ heterojunction also displayed excellent stability, which still kept above 90% degradation efficiency after five consecutive cycles. UV-Vis DRS and M-S analyses showed that the Fe₃O₄/Bi₂WO₆ catalyst has a strong visible light absorption capacity and the transfer pathway of photo-induced charge carriers. PL, EIS, and TPR showed that Fe₃O₄/Bi₂WO₆ has an efficient separation and transfer rate of the photo-generated carriers. ESR analysis proved that the superoxide radical (^•O₂ ^-) and hydroxyl radical (^•OH) play a major role in the Fe₃O₄/Bi₂WO₆ photocatalytic system. This special 2D/2D heterojunction we proposed may have huge potential for marine pollution treatment by photocatalysis degradation with dramatically boosted activities.