Abstract

• Perovskite LaCoO3 material was prepared by two different methods; citrate sol-gel and co-precipitation methods. The simple low temperature synthesis has been presented of single phased LaCoO3 for cathode application in solid oxide fuel cell (SOFC). The X-ray diffraction (XRD) shows that the hexagonal LaCoO3 phase was well formed at sintering temperature 900 °C in the citrate sol-gel and co-precipitation methods. Scanning electron microscopy (SEM) analysis indicates that the particle size of LaCoO3 powder varies from 20 nm to 60 nm depending on the preparation method. The FT IR spectra confirm that the absorption band of La-O and Co-O bonding appeared at 665, 592 and 406 cm-1 . The optical properties of LaCoO3 studied by UVvisible spectrophotometer in the wavelength range of 300 nm to 700 nm. The band gap values of the LaCoO3 prepared by citrate sol-gel method and by co-precipitation are 2.15 eV and 2.42 eV respectively. The dielectric properties and ac electrical conductivity have been investigated by LCR meter in the frequency range of 100- 1000 kHz. The ac electrical conductivity value of LaCoO3 prepared by citrate sol-gel method is 8.74 μΩcm-1 and by co-precipitation method is 4.38 μΩcm-1 respectively. The perovskite LaCoO3 prepared by citrate sol-gel method show highly dense structure, lower band gap value and high electrical conductivity than the LaCoO3 obtained by co-precipitation method.