Influence of semiconductor/insulator/semiconductor structure on the photo-catalytic activity of Fe3O4/SiO2/polythiophene core/shell submicron composite

he Fe3O4/SiO2/polythiophene [FSP] submicron composite [SC] with a structure of semiconductor/insulator/semiconductor [SIS] was obtained. The characterization results showed that the FSP SC had a spherical core/shell shape with an average diameter of 506 nm. The high saturated magnetization value (～39 emu/g) ensured the easy separation of FSP SC from aqueous solution. The photo-catalytic activity of the FSP SC was evaluated by the degradation of methyl orange (MO) under UV-irradiation in the presence of H2O2. Due to the SIS structure, the degradation rate constant by FSP SC (0.02177min?1) was 6.4, 1.6, and 2.5 times higher than that of Fe3O4/polythiophene (FP), polythiophene (P), and TiO2, respectively. The repetition results suggested the good photochemical stability of FSP SC. The mecha- nism was proposed by investigating the energy band variation of the SIS structure, the transfer of light generated carriers and the formation of effective hydroxyl radicals in the photo-catalysis progress.