Self-assembly of polyoxometalate-thionine multilayer films on magnetic microspheres as photocatalyst for methyl orange degradation under visible light irradiation.

(PW(12)-TH)(n) multilayer films (PW(12)=PW(12)O(40)(3-), TH=thionine) were deposited successfully on core-shell structured Fe(3)O(4)@SiO(2) magnetic microspheres through layer-by-layer (LbL) self-assembly method. The physical and photocatalytic properties of such magnetic microspheres coated with (PW(12)-TH)(n) films have been characterized by SEM, FTIR, and UV-vis spectra. The microspheres exhibit better photocatalytic activity toward the degradation of methyl orange (MO) under visible light irradiation than the quartz slides support. In addition, the use of magnetic support guarantees facile, clean, fast, and efficient separation of the photocatalyst after the degradation of MO. Such catalysts can be reused several times and display good reproducibility by magnetic separation.