Facile fabrication of magnetic Ag/ZnO/Fe3O4 composite and the photocatalytic performance under simulated sunlight irradiation

Abstract Magnetic Ag/ZnO/Fe3O4 composite was prepared by a moderate method without high temperature and high pressure. The characterization showed that Fe3O4 and metalic Ag nanoparticles were dispersed homogeneously on the surface of ZnO hexahedrons. And, the Ag/ZnO/Fe3O4 composite kept good crystallinity. Due to the introduction of Fe3O4 and metalic Ag nanoparticles, Ag/ZnO/Fe3O4 composite exhibited excellent absorption in the visible light region and showed good magnetic responsiveness. The photocatalytic reaction rate constant of Ag/ZnO/Fe3O4 composite under simulated sunlight irradiation reached to 0.134 min−1, which is twice of ZnO and 3.55 times of ZnO/Fe3O4 composite, exhibiting excellent photocatalytic performance. The improvement of photocatalytic performance could root in the SPR effect of Ag and the heterojunction between Ag and ZnO. Superoxide radical anions, hydroxyl radical and holes are main active species in the photocatalytic process. The reusability test showed that the removal rate of Ag/ZnO/Fe3O4 composite for MB reached to 97.31%, and kept 80.5% after five cycles and exhibited good reusability.