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

The Fe 3 O 4 /SiO 2 /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 H 2 O 2 . Due to the SIS structure , the degradation rate constant by FSP SC (0.02177 min −1 ) was 6.4, 1.6, and 2.5 times higher than that of Fe 3 O 4 /polythiophene (FP), polythiophene (P), and TiO 2 , respectively. The repetition results suggested the good photochemical stability of FSP SC. The mechanism 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.