G.Gokila Krishnan and

Abstract-- Nanocrystalline form of pure ceria (CeO2) and metal (Mg and Sc) doped ceria was obtained by co-precipitation technique. The metal loading was maintained at 10 mol % for both Mg and Sc dopants. The synthesized nanocrystalline form of powders was then subjected to different characterization techniques such as powder X-ray diffraction (XRD) for phase and structural identification. The composition and morphology was investigated using scanning electron microscopic analysis and energy dispersive X-ray spectrometry (EDS). The ionic conductivity due to the dopant effect was investigated using impedence spectroscopic analysis in the frequency range 50 Hz to 5 MHz. The impedance analysis reveals that the sample Ce0.9Mg0.1O2 was found to have higher ionic conductivity compared to Ce0.9Sc0.1O2 in the temperature range of 400–600°C. Nyquist plot shows the major contributions were due to the grain boundary resistance contributions which accounts for the higher ionic conductivity in case of the dopants. These dopant effect on the ceria was discussed in detail. Index Term-- Co-Precipitation method; Doped ceria; X-ra