Magnetically separable TiO2:: Preparation and photocatalytic properties

A magnetically separable photocatalyst TiO2/SiO2/NiFe2O4(TSN) was prepared by a liquid catalytic phase transformation method. The catalyst thus obtained shows high photocatalytic activity for the degradation of methyl orange in water under UV irradiation. The magnetic property measurements indicate that the photocatalyst possesses superparamagnetic nature. It can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. XRD and TEM were used to characterize the structure of photocatalyst TSN, indicating that the magnetic SN particle was compactly enveloped by P-25 titania, and TiO2 shell was formed. The degradation experiments of methyl orange indicated that the thin SiO2 layer between NiFe2O4 and TiO2 shell could improve the photocatalytic activity of TSN. The recycled TSN exhibited a good repeatability of the photocatalytic activity.