Synthesis and Characterization of La(Ce, Ba)NiO 3 Perovskite-Type Oxides

In this paper, an attempt was made to synthesize LaNiO 3 , CeNiO 3 , and BaNiO 3 , and Ce 3+ and Ba 2+ co-substituted LaNiO 3 . These samples were further subjected to various material characterization techniques in order to evaluate their physio-chemical properties. Scanning electron microscope (SEM) images showed large chunks of aggregated nanoparticles with minute voids. The EDX-derived atomic composition deviated from the nominal composition suggesting the occurrence of multiple phases. In addition, transmission electron microscope (TEM) images revealed that the samples exhibit uneven spherical shape with a high degree of aggregation. The Fourier transformed-infrared (FT-IR) spectra of the synthesized samples show vibrations of the BO 6 octahedral indicating the presence of Ni–O bonds. In addition, metal-carboxyl vibrations were identified from the peaks at 1400 and 860 cm −1 . Optical diffuse reflectance spectra (DRS) showed certain peaks originating from the O 2− (2 p ) → Ni 2+ (3 d ) charge transfer. The X-ray powder diffraction (XRPD) analysis revealed the existence of multiple phases for the samples CeNiO 3 , BaNiO 3 , and La(Ce, Ba)NiO 3 . Moreover, La(Ce, Ba)NiO 3 contained four phases showing that the co-substitution of Ba 2+ and Ce 3+ into LaNiO 3 may require more sophisticated methodologies. The sample BaNiO 3 showed maximum weight loss, due to the existence of carbonate phase. The dielectric properties decreased with increasing frequency, while the ac electrical conductivity enhanced with increasing frequencies obeying the Maxwell–Wagner two-layer model in accordance with Koop’s phenomenological theory.