Synthesis of Lanthanum Nickelate and Praseodymium Substituted Compounds by Molten Salt Technique

Abstract

Lanthanum Nickelate (LaNiO3) and Praseodymium (Pr) substituted compounds were prepared by molten flux method using chloride precursors. The investigation presents the characterization of the synthesized materials using TGA/DTA, XRD, FTIR, CHNS, EDAX, UV-visible, EPR spectral and SEM studies. The thermo gravimetric analysis reveals the decomposition and thermal reactions of the precursors at different temperature regions. The XRD analysis shows that the synthesized crystals have the rhombohedral structure. FTIR spectra exhibit the absorption bands for the O-H stretching vibration and Ni-O bands at different wave lengths. A shift in band position has been observed on the substitution of Pr3+ions in the parent compound. The CHNS analysis presents the impurities level in the synthesized compounds. The EDAX analysis shows the concentration of La, Ni, Pr and O in the synthesized compounds. The band gap of the material has been determined from UV spectra and it is found to be 4.96 eV for the parent compound. The lone pair of electron state is identified from the EPR spectra. The SEM micrographs have shown the presence of fine crystallites with irregular morphology. The average particle size of the powders is ranging between 25-35 μm. From the above studies, it has been concluded that pure crystals of LaNiO3and Praseodymium substituted compounds can be conveniently synthesized by molten salt technique.