Preparation and photocatalytic properties of hybrid core–shell reusable CoFe2O4–ZnO nanospheres

Magnetically separable and reusable core–shell CoFe2O4–ZnO photocatalyst nanospheres were prepared by the hydrothermal synthesis technique using glucose derived carbon nanospheres as the template. The morphology and the phase of core–shell hybrid structure of CoFe2O4–ZnO were assessed via TEM, SEM and XRD. The magnetic composite showed high UV photocatalytic activity for the degradation of methylene blue in water. The photocatalytic activity was found to be ZnO shell thickness dependent. Thicker ZnO shells lead to higher rate of photocatalytic activity. Hybrid nanospheres recovered using an external magnetic field demonstrated good repeatability of photocatalytic activity. These results promise the reusability of the hybrid nanospheres for photocatalytic activity.

► Synthesis of novel hybrid magnetic-ZnO core–shell composite nanospheres.
► High photocatalytic activity of hybrid nanospheres was noted as compared to that of pure ZnO nanoparticles.
► The hybrid nanospheres could be easily retrieved using an external magnet for repeated use.
► Repeated use of hybrid nanospheres did not show any degradation in the photocatalytic activity.
► The photocatalysis rate was observed to be ZnO shell thickness dependent.