Investigation of multiferroic and photocatalytic properties of Li doped BiFeO3 nanoparticles prepared by ultrasonication

Abstract

The nominal composition of BiFe1ð€€€xLixO3 (x = 0.00, 0.06 and 0.12) bulk polycrystalline materials were synthesized by a conventional solid state reaction technique and by using ultrasonication technique corresponding nanoparticles were produced directly from their bulk powder materials. The XRD patterns con rmed the rhombohedrally distorted perovskite structure of the synthesized samples. The Field Emission Scanning Electron Microscopy (FESEM) images and their respective histograms demonstrated that the grain size distributions are homogeneous and the average grain sizes increased with the increase of Li concentration in BiFeO3 bulk materials. In BiFeO3 nanoparticles, the particle sizes were reduced with Li substitution. The X-ray Photoelectron Spectroscopy (XPS) analysis con rmed the substitution of Li in BiFeO3 bulk and nanoparticles, respectively and the phase purity of the compound as well. The leakage current density of the nanoparticles was much smaller than that of the bulk polycrystalline materials and the polarization (P) versus electric eld (E) hysteresis loops were typical for the nanoparticles compared to their corresponding bulk counterparts. The absorption spectra con rmed that the visible-light-induced undoped and doped BiFeO3 can absorb light with wavelength from UV to visible region. In photocatalytic activity test, the higher photodegradation rate was found for 12% Li-doped BiFeO3 nanoparticles. The improved magnetization was observed with the substitution of Li in BiFeO3 bulk materials and the magnetization was decreased for Li-doped BiFeO3 nanoparticles. The magnetic properties in Li doped BiFeO3 nanoparticles is expected to associate with size reduction of the particles, suppression of impurity phases, structural transition and also amorphization of the materials due to ultrasonication.