Magnetically separable core-shell ZnFe₂O₄@ZnO nanoparticles for visible light photodegradation of methyl orange

Visible light photodegradation of aqueous methyl orange using magnetically separable core-shell ZnFe₂O₄@ZnO nanoparticles is reported. A combination of low temperature (190 °C) microwave synthesis and hydrothermal method were used to prepare phase pure material with excellent yield (95%). The magnetic separability, surface area of 41 m²/g and visible light absorption make ZnFe₂O₄@ZnO nanoparticles a good solar photocatalyst. ZnFe₂O₄@ZnO displayed greater UV photocatalytic efficiency than ZnO owing to the generation of large number of electron-hole pairs. Visible light photodegradation of MO using ZnFe₂O₄@ZnO nanoparticles is reported for the first time. Higher first order rate constants under both UV and visible light for core-shell nanoparticles suggested their superiority over its individual oxides. The ZnFe₂O₄@ZnO showed excellent reusability with high photocatalytic efficiencies suggesting its suitability for solar photocatalytic applications.