Enhanced photocatalytic activity in ZnFe2O4–ZnO–Ag3PO4 hollow nanospheres through the cascadal electron transfer with magnetical separation

Magnetically separable ZnFe2O4–ZnO–Ag3PO4 hollow nanospheres were successfully synthesized using phenolic formaldehyde microspheres as template via impregnating-calcination process. The photocatalytic activity under visible light irradiation increases in the order of ZnFe2O4–ZnO–Ag3PO4 > ZnFe2O4–Ag3PO4 > Ag3PO4 > ZnFe2O4–ZnO > ZnFe2O4. The enhanced activity could be attributed to the cascade electron transfer from ZnFe2O4 to ZnO then to Ag3PO4 through the interfacial potential gradient in the ternary hybrids conduction bands, which facilitates the charge separation and retarded the charge pair recombination. Furthermore, ZnFe2O4–ZnO–Ag3PO4 hollow nanospheres could be conveniently separated by using an external magnetic field, and the study also provides a general and effective method in the composite hollow nanomaterials with sound heterojunctions that may show a variety of applications.