Synthesis and effect of annealing temperature on the structural, magnetic and photocatalytic properties of (La0.5Bi0.2Ba0.2Mn0.1)FeO(3−δ)

Novel La0.5Bi0.2Ba0.2Mn0.1FeO3−δ, with a perovskite-like structure, was synthesized by using the citric acid sol-gel route. The powder was precalcined at 400 °C and then separate portions were annealed at temperatures of 500, 600, 700, 800 and 900 °C. Transmission electron microscopy and powder X-ray diffraction analysis of the powders showed that they contain crystalline rhombohedral perovskite-type nanoparticles. The BET specific surface areas ranged between 4.19 and 27.8 m2 g−1, decreasing with increasing annealing temperature. Vibrating sample magnetometer analysis of the hysteresis loops showed an increase in coercive field with increasing annealing temperature. Very large coercive fields of about 5.60 kOe were obtained for samples annealed at 900 °C. This could prove useful in making magnetic recording materials. Photoluminescence spectroscopy showed that all the powders were active in the visible region and could be useful for visible light photodegradation of pollutants. The powders were all screened for photocatalytic activity against an organic dye (rhodamine B) in the visible region of the solar spectrum and the photocatalytic activities were good particularly for powders annealed at 900 °C.