Synthesis and characterization of mixed oxides derived from lanthanum orthoferrite perovskite: exploring morphological, spectroscopic, and photocatalytic properties

Abstract

We synthesized pure and doped gadolinium, samarium, and chromium LaFeO3 denoted as LFO, LFCO, LGFCO, and LSFCO, respectively, employing a straightforward, cost-effective, and environmentally friendly solid-state method. The resulting samples were characterized through powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), and UV–Visible absorption measurements. The PXRD findings affirmed that the phase structures corresponding to LFO, LFCO, LGFCO, and LSFCO manifested at an identical calcination temperature of 1200 °C, adopting orthorhombic systems. The calculated crystallite size for each sample, employing Debye-Scherrer’s equation, ranged from 25 to 37 nm, with LGFCO and LSFCO exhibiting an augmented crystallite size. This enhancement can be attributed to the integration of dopants into the LaFeO3 lattice, facilitating crystallite growth. SEM images portrayed microstructure composed of fine particle sizes and pseudo-spherical morphology, and the stoichiometry of La, Fe, and O in LFO was confirmed by energy dispersive spectroscopy (EDS). Reduction in the band gap was ascribed to the doping effect, with LGFCO exhibiting the lowest band gap value. Notably, this ceramic material demonstrated the highest photocatalytic activity for methylene blue degradation under sunlight radiation, surpassing the performance of the other examined samples.