Fabrication and photocatalytic activity of magnetic core@shell ZnFe₂O₄@Ag₃PO₄ heterojunction

Novel ZnFe₂O₄@Ag₃PO₄ core@shell heterojunction photocatalysts were fabricated through a solvothermal-liquid phase deposition method. Ag₃PO₄ was evenly dispersed on the surface of ZnFe₂O₄ microrods and approximately 150 nm in size. ZnFe₂O₄@Ag₃PO₄ composite photocatalysts could be recovered rapidly using the ferromagnetism of ZnFe₂O₄. Experimental results from the photodegradation of methylene blue (MB) indicated that the 14 wt% ZnFe₂O₄@Ag₃PO₄ photocatalyst sample showed the best catalytic activity by degrading 93% MB after 6 min of irradiation，the rate of degradation of the composite was 1.39 and 11.6 times those of Ag₃PO₄ and ZnFe₂O₄, respectively, which is attributed to the effective charge separation by the core@shell heterojuction between the ZnFe₂O₄ and Ag₃PO₄．The main mechanism during degradation was the direct oxidation by the photo-induced holes.