Collating the structural, vibrational, and photocatalysis properties of LaFeO3 rare-earth orthoferrite nanoparticles synthesized by the sol-gel method

Abstract

To synthesize the rare earth orthoferrite \({LaFe}{O}_{3}\) nanopowder, a perovskite, a sol-gel technique was employed. The resulting particles were characterized using SEM, XRD, and UV-visible absorption spectroscopy. The perovskite structure of \({LaFe}{O}_{3}\) (with La having an ionic radius of 1.36 Å) exhibits internal deformation due to the large ionic radii of the elements occupying the A-site. This deformation affects several of its desirable properties. Notably, there is a reduction in lattice parameters and an increase in octahedral distortion. Deviations in the Raman modes can indicate spin-phonon coupling in \({LaFe}{O}_{3}\) additionally, increased crystalline distortions can hinder the spin-lattice interactions, leading to adverse effects.The particles were found to be uniformly spherical, with an average size of 80 nm. The optical energy band gap of \({LaFe}{O}_{3}\) at the nanoscale was measured to be 2.1 eV. This structure was further confirmed through optical absorbance and Raman spectroscopy measurements, aided by spin-phonon coupling. The optical characteristics exhibit intriguing variations that correlate with the expected photocatalytic activities. The photocatalytic activity of \({LaFe}{O}_{3}\) nanoparticles was evaluated through the UV degradation of various organic dyes, including acid fuchsine (AF), methyl orange (MO), rhodamine B (RhB), and methylene blue (MB). Notably, the dyes underwent substantial photocatalytic degradation when exposed to visible light.

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