Temperature Dependent Photocatalytic Activity of Bifeo₃ Nanoparticles by Sol Gel Method

Abstract

The synthesis of ethylene glycol (EG) based Bismuth Ferrite (BiFeO3) (BFO) nanoparticles were carried out with molar ratio of Bi:Fe as 1:1 annealed at different temperatures for 4 h by auto combustion sol-gel technique. The purity of phase, crystal structure and microstructure of sample was examined by using X-ray Diffraction Spectrometer (XRD) and Field Emission Scanning Electron microscopy (FESEM). The obtained results of XRD pattern of BFO demonstrated the presence of rhombohedral phase and perovskite crystal structure. The FESEM micrograph of synthesized sample gave brief picture of structure pattern of BiFeO3 nanoparticles which follows an agglomerated form with nearly spherical morphology. The presence of different functional groups in sample was examined by using Fourier Transform Infrared spectroscopy (FT-IR). The energy band gap of BFO was investigated by using UV-Visible absorbance spectroscopy. The stability of sample under various temperatures was investigated by using thermo gravimetric and differential scanning calorimetry (TGA-DSC). Further the photocatalytic activity of BiFeO3 nanoparticles was investigated by observing through degradation of methylene blue in an aqueous solution under incident visible light. In this study, the photocatalytic mechanism of BFO is proposed through the computation of band position and various indicative experiments. It was observed that produced hydroxyl radicals from electron hole pairs were the major reactive species accountable for the pollutant decomposition. In addition, with variation of the annealing temperature, crystallinity and mean crystallite size of BFO sample could be changed which in turn affected the photocatalytic performance of the corresponding samples.