Abstract

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Novel perovskite-type nanomaterials with the composition La1-x(Bix)FeO3-δ (where x = 0.5 and 0.2) were synthesized by using a modified citric acid sol-gel route and annealed at 900 °C in (1) in air (LB0.5FO-air and LB0.2FO-air), and (2) in Argon atmosphere (LB0.5FO-Ar and LB0.2FO-Ar). Scanning electron microscopy and powder X-ray diffraction analysis of the powders showed that they contain crystalline perovskite-type nanoparticles with crystallite sizes 37-41 nm. The lattice parameters, after refinement, showed that the particles crystallized in an orthorhombic structure. The BET specific surface areas (SSA) ranged between 1.76-4.37 m2 g -1 with powders synthesized under argon having the higher SSAs. Vibrating sample magnetometer analysis of the hysteresis loop showed a slightly higher magnetization value for the samples synthesized in air. Photoluminescence spectroscopy showed that the powders were all active in the visible region and could be useful for visible light photodegradation of organic dyes. 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 for powders synthesized in argon, In addition, a mineralization of up to 80% was achieved after 3 hrs of photodegradation for these powders as well. The materials therefore, show good potential for the photocatalytic degradation of organic pollutants and photocatalyst recovery after photodegradation

Keywords: perovskites, magnetisation, photoluminescence, photocatalytic activities