Magnetically recyclable ZnFe2O4-Fe2O3-Ag hollow nanophotocatalysts to decompose rhodamine B

Environmental pollution and energy exhaustion threaten human existence, and the exploitation of nanocatalysts offers new efficient ways to solve the pollution and energy crisis. However, the nanophotocatalysts are difficult to recycle because of its small size and low density. In this work, the magnetically recyclable ZnFe2O4-Fe2O3-Ag hollow nanophotocatalyst was successfully prepared via the process of impregnating, calcination and photoreduction. ZnFe2O4-Fe2O3-Ag possesses a hollow nanocore-shell structure with a particle size distribution of about 240 nm and a shell thickness of about 15 nm. In the hollow nanoternary complex of ZnFe2O4-Fe2O3-Ag, ZnFe2O4 and Fe2O3 have photocatalytic properties and magnetic properties, playing a recyclable and photocatalytic role, and both of them can form a matching heterojunction each other, which can further improve the photodegradation performance. Ag can capture electrons to inhibit photogenerated carrier recombination. The hollow core-shell structure can improve the utilization rate of light and the contact frequency with pollutants. The results of the photocatalytic activity to decompose rhodamine B under visible light irradiation as driving force reveal the sequence: ZnFe2O4-Fe2O3-Ag > ZnFe2O4-Fe2O3 > ZnFe2O4. ZnFe2O4-Fe2O3-Ag can be conveniently separated from water in magnetic environment and recycled. This work also affords a new method to prepare ZnFe2O4-based hollow nanoatalysts with facile recovery and form an excellent ternary composite.