LAUSR

Abstract A novel magnetically separable three-dimensional (3D) γ-Fe2O3@ZnO core-shell photocatalyst was successfully fabricated by hydrothermal-sintering and a subsequent atomic layer deposition (ALD) method. The uniform and conformal ZnO shell layer was precisely deposited on γ-Fe2O3, improving the specific surface area and surface potential. The photocatalytic capacity of γ-Fe2O3@ZnO composite was investigated by ciprofloxacin degradation. Results showed that the γ-Fe2O3@ZnO exhibited excellent degradation efficiency under simulated sunlight irradiation. The first-order kinetic rate constant of γ-Fe2O3@ZnO was demonstrated to be almost 4 and 20 times higher that of pure ZnO and γ-Fe2O3. Moreover, the recycling degradation experiments revealed that the γ-Fe2O3@ZnO core-shell photocatalyst was stable and reusable, which could be easily separated under an additional magnetic field. The mechanism of the remarkably enhanced photocatalysis was further explored by analyzing its heterostructure and determining the role of active radicals. The newly-designed type II heterostructure facilitated the separation of photo-induced carriers. Radical-trapping tests indicated that the holes and hydroxyl radicals played major roles in ciprofloxacin degradation. In prospect, the magnetic 3D γ-Fe2O3@ZnO core-shell photocatalyst has great potential for degradation of other refractory contaminants in water with solar light irradiation.