Visible light-assisted ferro-photocatalytic application of bismuth ferrite nanoparticles synthesized at low temperature

Abstract

Polycrystalline nano-sized multiferroic bismuth ferrite was prepared by facile sole-gel method using acetic acid as a chelating agent followed by calcination at 450, 500, and 600 °C. Transmission electron spectroscopy and X-ray diffraction patterns revealed the crystallinity in the samples, and the crystallite size increased with calcination temperature. The calcination temperature also greatly influenced the grain size of the materials, and high calcination temperature induces a decline in the total surface area per unit mass of material. The ferroelectric polarization measurement showed a decrease in remnant polarization from 0.18 to 0.09 μC/cm2 with an increase in temperature. The remnant polarization induced delayed recombination of charge carriers upon light illumination, and the high surface area led to the highest photocatalytic activity in 450 °C calcined samples. The higher photocurrent density in low-temperature calcined samples supports the visible-light photodegradation studies of Congo Red (CR) dye. A maximum of 76.6% photocatalytic activity was observed in the 450 ℃ calcined bismuth ferrite samples. In summary, the higher photocatalytic efficiency in the low-temperature samples is attributable to the synergistic effect of relatively higher remnant polarization and higher surface area.