Preparation of bismuth ferrite nanoparticles and their photocatalytic activity for MO degradation

A modified polyacrylamide gel method was used to fabricate Bi2Fe4O9 nanoparticles. Thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) analysis, fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were used in combination to investigate the thermal decomposition process of xerogels and the formation of Bi2Fe4O9 phase. It is demonstrated that high-phase-purity Bi2Fe4O9 nanoparticles can be prepared at a calcining temperature of 750 °C. Scanning electron microscope (SEM) observation reveals that the prepared Bi2Fe4O9 nanoparticles are nearly spherical in shape, exhibit a smooth surface, feature no agglomeration character, and have an average diameter of about 220 nm. Ultraviolet-visible diffuse reflectance spectroscopy was used to investigate the light-absorbing properties of Bi2Fe4O9 nanoparticles, and the value of the optical bandgap energy is obtained to be 2.08 eV. The photocatalytic activity of Bi2Fe4O9 nanoparticles was evaluated by the degradation of methyl orange (MO), a typical azo dye. The experimental results reveal that the product exhibits a pronounced photocatalytic activity for the MO decomposition under ultraviolet and visible-light irradiation.