Synthesis and Characterizations of BiFeO₃ Nanoparticles for Photocatalytic Application

Bismuth ferrite (BiFeO 3 ) nanoparticles were synthesized using sol‐gel method and annealed at 450 °C, 550 °C, 650 °C, and 750 °C for 2 hours. The role of annealing temperature on structural, optical, magnetic, and dielectric properties of BiFeO 3 nanoparticles was studied. XRD patterns of BiFeO 3 nanoparticles confirm the rhombohedral structure with a mean crystallite size of 40 nm. The optical bandgap of the BiFeO 3 nanoparticles increased from 1.9 eV to 2.02 eV with annealing temperature. From photoluminescence spectra, it was observed that the BiFeO 3 nanoparticles showed a clear emission peak at 565 nm and its intensity decreased with annealing temperature. Magnetic properties of the BiFeO 3 nanoparticles were studied at room temperature and different magnetic behaviours were found in BiFeO 3 nanoparticles. The BiFeO 3 nanoparticles exhibited ferromagnetism at low annealing temperatures and diamagnetic nature at high annealing temperatures. The AC conductivity studies showed that BiFeO 3 nanoparticles possess a dielectric constant of 170 with the least dielectric loss. The BiFeO 3 nanoparticles annealed at 750 °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.