Magnetically Recyclable Fe₃O₄@Zn _xCd_{1- x}S 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 _xCd_{1- x}S, 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@Zn_0.55Cd_0.45S 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.