Characterization of B site codoped LaFeO₃ nanoparticles prepared via co-precipitation route

LaFe_1−x−y Co _x Pd _y O₃ [(x, y) = (0, 0), (0.40, 0), (0.38, 0.05)] nanoparticles were synthesized via a co-precipitation route using ammonium hydroxide, sodium hydroxide and ammonium carbonate as the precipitant and calcination at different temperatures to study the compositional driven structural changes in lanthanum ferrites. Analysis of X-ray diffraction (XRD) patterns confirms the formation of single-phase perovskite structure and existence of orthorhombic Pnma symmetry for calcined powders. Field emission scanning electron microscope (FESEM) observations show that Pd-doped powders yield finer particles along with narrower particle size distribution compared with LaFeO₃ and LaFe_0.6Co_0.4O₃. Moreover, using ammonia as the precipitant leads to a smaller mean particle size of powders compared to NaOH, as well as significant difference in morphology of the particles. Raman analysis reveals that both Co and Pd atoms substitute Fe site in perovskite structure with shifting of phonon modes. Comparing Raman spectra demonstrates the presence of more oxygen vacancies in Pd-doped perovskites. It can be concluded from the results that Pd is successfully incorporated into the perovskite structure by co-precipitation method.