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

•Phase pure, magnetic ZnFe2O4@ZnO nanoparticles synthesized with excellent yield.•ZnFe2O4@ZnO displayed higher UV photocatalytic efficiency than ZnO nanoparticles.•First report on visible light photodegradation of methyl orange by ZnFe2O4@ZnO.•Excellent reusability of ZnFe2O4@ZnO nanoparticles observed for azo dye removal.

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.

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