Controllable synthesis of magnetic Fe3O4 encapsulated semimetal Bi nanospheres with excellent stability and catalytic activity

Abstract

Novel core–shell magnetic Bi@Fe3O4 nanostructures with excellent stability and catalytic activity were prepared by depositing magnetic Fe3O4 onto the surface of semimetal Bi nanospheres. X% Bi@Fe3O4 nanocomposites were prepared with proportions of 5, 15, 30, 50% by varying the content of the added element Bi. The nanocomposites were characterized by XRD, TEM, EDS, XPS, BET, and UV–Vis DRS. The results of the experiments indicated that the diameters of the nanospheres were controlled within approximately 100–300 nm. With increasing of Bi content, the size of the nanosphere was more uniform and the surface smoother. The 30% Bi@Fe3O4 nanocomposite showed the highest photocatalytic activity based on the degradation of rhodamine B under visible light irradiation. Moreover, Bi@Fe3O4 could be separated and collected easily using an external magnetic field. The catalyst retained its high activity after four photoreaction cycles. Given the excellent stability and catalytic activity of the Bi@Fe3O4 nanocomposite, it displays high potential for a broad range of applications.