Synthesis of urchin-like Fe3O4@SiO2@ZnO/CdS core–shell microspheres for the repeated photocatalytic degradation of rhodamine B under visible light†
Abstract
Herein, we developed the design and synthesis of urchin-like Fe3O4@SiO2@ZnO/CdS core–shell microspheres, in which the multiple functional components were integrated successfully into a single microcomposite. The morphology, composition, and optical and magnetic properties of those core–shell microspheres were characterized by various analytical techniques. Photocatalytic performances were evaluated by the photocatalytic elimination of rhodamine B (RhB) under visible light irradiation. Compared with the Fe3O4@SiO2@ZnO microspheres, the Fe3O4@SiO2@ZnO/CdS microspheres show remarkably enhanced visible light photocatalytic activity, benefiting from the sensitization of CdS, which can extend the visible light absorption and facilitate the separation of photoinduced carriers. The amount of CdS in the core–shell microspheres can be controlled by adjusting the SILAR cycles. The effect of the CdS loading amount on the photocatalytic activity was also investigated and the results indicate that Fe3O4@SiO2@ZnO/CdS with 10.1 wt% CdS exhibits the best photocatalytic ability. Furthermore, it is worth noting that these multifunctional microspheres exhibit excellent magnetic response and high stability. The core–shell photocatalysts can also maintain high photocatalytic activity even after running for five cycles.