Oxide ionic conductivity and microstructures of Pr and Sm co-doped CeO2-based systems

Abstract

The compositions Ce0.80Sm0.2-xPrxO3 (x=0-0.12) were prepared through the citrate-nitrate method. The synthesized Pr3+ and Sm3+ co-doped ceria powders with different compositions were calcined at 600 degrees C for 3 h. Phase structure of the calcined powders was characterized by X-Ray diffraction (XRD) analysis. All the calcined samples were found to be ceria based solid solutions of fluorite type structures. The morphology examinations were carried out by scanning electron microscopy (SEM) analysis. Relative density of more than 91% of the theoretical can be achieved by sintering the Ce0.80Sm0.2-xPrxO2-delta pellets at 1400 degrees C for 6 h. The two-probe a.c. impedance spectroscopy was used to study the ionic conductivity of the doped ceria samples. The Ce0.80Sm0.08Pr0.12O1.90 composition showed the highest total ionic conductivity value which is 2.39 x 10(-2) S/cm at 600 degrees C.