The co-doped ceria-based materials
with general composition formula Ce0.8-xYxSm0.2O2-δ (x = 0, 0.02, 0.04, 0.06)
were prepared through the sol-gel method. The single phase of the prepared
materials was confirmed by X-ray diffraction (XRD). The lattice parameters were
determined by least square fitting of UNIT CELL programme. The linear variation
of lattice parameter with concentration of Y
into the samarium doped ceria (SDC) indicates the validity of Vegard’s law.
The crystallite size of the samples obtained by using of Scherrer formula is in
the range from 34 nm to 49 nm. The thermal expansion studies were carried out by using
dilatometric technique in the temperature range from room temperature to 1000°C.
It was observed that the thermal expansion increased linearly with increasing
temperature for all the samples. The electrical conductivity was studied using
impedance spectroscopy. It was observed that the composition Ce0.74Y0.06Sm0.2O2-
Ceria based electrolyte materials are very useful in intermediate-temperature solid oxide fuel cell (IT-SOFC). The compositions Ce0.85Gd0.15 - xCaxO2 - δ (x = 0.0 - 0.075) were prepared through sol-gel method. Their structure was studied by X-ray diffraction. Dense ceramic Ce0.85Gd0.15 - xCaxO2 - δ samples were prepared by sintering the pellets at 1300°C. The lattice parameter was calculated by Rietveld refinement of XRD patterns. Four probe A.C. impedance spectroscopy was used to study the total ionic conductivity of doped and co-doped ceria ceramics in the temperature range 200°C -