Structural, optical and photocatalytic properties of Sr-doped and Ca-doped BiFeO3 compounds prepared by Pechini method

BACKGROUND BiFeO3 is an important new visible-light photocatalyst for the removal of organic pollutants, the efficacy of which is related to its narrow band gap energy (2.2 eV) and excellent chemical stability. In this work, the effects of Sr and Ca doping on the structural and photocatalytic properties of BiFeO3 were investigated. RESULTS X-ray diffraction results revealed the formation of a rhombohedral structure (R3c), as well as the successful incorporation of Sr2+ and Ca2+ ions into the BFO structure. The nanometric size of the specimens was in the range 23-55 nm. The percentage of structural phases in the obtained compounds was calculated by Rietveld analysis. Scanning electron microscopy results showed changes in the morphology and grain sizes. The band gap values of the ceramics display a gradual reduction when the dopant concentration is increased. The surface analysis by X-ray photoelectron spectroscopy revealed, for all compounds, the characteristic peaks of Fe and Bi, as well as Sr and Ca in the doped samples. CONCLUSION The photocatalytic activity of the prepared photocatalyst was evaluated by the removal of methylene blue and 4-chlorophenol. The doped samples showed higher photocatalytic activity compared to the undoped BiFeO3 sample, attributed to the enhanced visible light absorption, the synergistic effects of the BiFeO3 and Bi2Fe4O9 phases, as well as the successful separation of photogenerated electrons and holes induced by Sr and Ca doping. (c) 2022 Society of Chemical Industry (SCI).