Preparation of magnetic photocatalyst TiO2 supported on NiFe2O4 and effect of magnetic carrier on photocatalytic activity

A magnetic photocatalyst TiO2/NiFe2O4 (TN) with typical ferromagnetic hysteresis was prepared by a sol-gel method, which is easy to be separated from a slurry-type photoreactor under the application of an external magnetic field, being one of promising photocatalysts for wastewater treatment. The analysis of XRD indicated that the highly dispersed NiFe2O4 nanoparticles prevented the formation of rutile phase to some extent. A transmission electron microscope (TEM) was used to characterize the structure of the photocatalyst, indicating that the NiFe2O4 nanoparticles highly dispersed among TiO2 nanoparticles. The prepared photocatalyst showed high photocatalytic activity for the degradation of methyl orange in water. The degradation results revealed that the NiFe2O4 nanoparticles played the role of recombination centre of photogenerated electrons and holes for the TN photocatalyst, which gave rise to the decrease in photocatalytic activity. Moreover, the experiment on recycled use of TN demonstrated a good repeatability of the photocatalytic activity.