Synthesis and Characterizations of BiFeO3 Nanoparticles for Photocatalytic Application

Bismuth ferrite (BiFeO3) nanoparticles were synthesized using sol-gel method and annealed at 450 degrees C, 550 degrees C, 650 degrees C, and 750 degrees C for 2 hours. The role of annealing temperature on structural, optical, magnetic, and dielectric properties of BiFeO3 nanoparticles was studied. XRD patterns of BiFeO3 nanoparticles confirm the rhombohedral structure with a mean crystallite size of 40 nm. The optical bandgap of the BiFeO3 nanoparticles increased from 1.9 eV to 2.02 eV with annealing temperature. From photoluminescence spectra, it was observed that the BiFeO3 nanoparticles showed a clear emission peak at 565 nm and its intensity decreased with annealing temperature. Magnetic properties of the BiFeO3 nanoparticles were studied at room temperature and different magnetic behaviours were found in BiFeO3 nanoparticles. The BiFeO3 nanoparticles exhibited ferromagnetism at low annealing temperatures and diamagnetic nature at high annealing temperatures. The AC conductivity studies showed that BiFeO3 nanoparticles possess a dielectric constant of 170 with the least dielectric loss. The BiFeO3 nanoparticles annealed at 750 degrees C were studied for photocatalytic properties and showed good photocatalytic activity in the visible region. A prominent absorption peak at 663 nm in absorption spectra due to MB and it confirm the utility of BFO as photocatalyst applications.