Microstructure and Electrical Conductivity of Ce0.85Y0.15-xRExO2-/ (RE=Pr,Tb)

Ce0.85Y0.15-xRExO2-δ (RE=Pr,Tb) with x = 0.02 and 0.06 solid solutions were synthesized by the coprecipitation technique to study the effect of Pr and Tb additions in the microstructure and electrical conductivity of yttria-doped ceria solid electrolyte. For comparison purposes, the solid solution Ce0.85Y0.13Pr0.02O2-δ was prepared by mixing Pr6O11 to the precipitated gel of ceria-yttria. Reductions in the average grain size and in the full width at half maximum height of the grain size distribution curve were obtained with increasing praseodymium additions to ceria-yttria. In contrast, Tb additions to yttria-doped ceria do not result in any significant microstructural change. Although an increase in grain conductivity with small amounts of Pr was observed at 300 ºC, both co-dopants exert a deleterious effect on the electrical conductivity of yttria-doped ceria at temperatures of typical solid oxide fuel cells operation.