Magnetically Recyclable Fe3O4@Zn xCd1- xS Core-Shell Microspheres for Visible Light-Mediated Photocatalysis.

Magnetically recyclable photocatalyst has drawn considerable research interest because of its importance in practical applications. Herein, we demonstrate a facile hydrothermal process to fabricate magnetic core-shell microspheres of Fe3O4@Zn xCd1- xS, successfully using Fe3O4@ZnS core-shell microspheres as sacrificed templates. The as-prepared magnetically recyclable photocatalysts show efficient photochemical reduction of Cr(VI) under irradiation of visible light. The photochemical reduction mechanism has been studied to illustrate the reduction-oxidation ability of the photogenerated electrons (e-) and holes (h+), which play an important role in the reduction of Cr(VI) to Cr(III) and oxidation of organic dyes. The as-prepared Fe3O4@Zn0.55Cd0.45S core-shell microspheres show good chemical stability and only a slight decrease in the photocatalytic activity after four recycles. In particular, the as-prepared photocatalysts could be easily recycled and reused by an external magnetic field. Therefore, this work would provide a facile chemical approach for controlled synthesis of magnetic nanostructures combined with alloyed semiconductor photocatalysts for wastewater treatment.