Effect of dopant on the thermal and electrical behavior of nanostructured ceria materials

Nanopowders with compositions Ce0.8Gd0.2O2−δ (CG), Ce0.8Sm0.2O2−δ (CS), and Ce0.9Eu0.1O2−δ (CE) have been synthesized by a modified Pechini method. X-ray diffraction (XRD) revealed that all powders calcined at 550°C were single phase, with the cubic fluorite-type structure. The good sintering properties of the synthesized nanopowders allowed us to obtain dense ceramics (>97% theoretical density). The ionic conductivities of doped ceria ceramics were investigated as a function of temperature by using AC impedance spectroscopy in the temperature range 300–800°C. The best conductivity was evidenced for the Ce0.8Sm0.2O2−δ sample.