Magnetic core-shell ZnFe₂O₄/ZnS nanocomposites for photocatalytic application under visible light

Magnetic core-shell ZnFe₂O₄/ZnS composites were synthesized through a two-step chemical process including the hydrothermal and the co-precipitation methods. The structural characterization revealed that the composites consisted of a layer of ZnS clusters on the surface of ZnFe₂O₄ nanoparticles. The band gap energy of the composite was estimated to be 2.2eV through the Kubelka-Munk plot, implying the possible application as a photocatalyst under the visible light radiation. The improved photocatalytic efficiency of the ZnFe₂O₄/ZnS composites was confirmed through the photocatalytic degradation of Methyl Orange. The increased absorption of the visible light and the enhanced separation of the electron-hole pairs due to the relative energy band positions in ZnFe₂O₄ and ZnS are considered as the main advantages. Additionally, the moderate magnetization of the ZnFe₂O₄ core insured the easy magnetic collection of the composite materials without affecting the photocatalytic performance. Our results showed that ZnFe₂O₄-based nanocomposites could be used as an effective and magnetic retrievable photocatalyst.