Effect of magnetic carrier NiFe2O4 nanoparticles on physicochemical and catalytic properties of magnetically separable photocatalyst TiO2/NiFe2O4

Abstract

A series of magnetically separable photocatalyst TiO2/NiFe2O4(TN) with different mass ratios of NiFe2O4 to TiO2 was prepared by sol-gel method. The X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM), ultraviolet-visible spectroscopy(UV-Vis), Brunauer-Emmett-Teller(BET) surface analysis and photoluminescence spectroscopy(PL) were used to characterize the photocatalyst TN. The XRD patterns of TN indicate that adulterating a smidgen of NiFe2O4 into TiO2(about 0.1%, mass ratio) can promote the phase transformation of TiO2, however, when the doped amount of NiFe2O4 surpasses 1%, the introduction of NiFe2O4 can inhibit the growth of TiO2 crystal grain and reduce the size of TiO2 crystal grain. The XPS results of TN indicate that some Fe3+ replace Ti4+ of the TiO2 lattice forming Fe-O-Ti bonds. The PL analysis of TN shows that the NiFe2O4 nanoparticles in photocatalyst TN play the role of the effective recombination centre of the photogenerated electrons and holes, leading to the decrease in photocatalytic activity.