Chemical Expansion and Frozen-In Oxygen Vacancies in Pr-Doped Ceria

Abstract

Doped CeO2 is a promising candidate for solid oxide fuel cell electrolyte and electrode applications because of its high ionic conductivity and reduction/oxidation behavior at intermediate temperatures. Its electronic and ionic properties and microstructural stability are of particular interest. The present study demonstrates that the large number of oxygen vacancies created in PrxCe1-xO2-δ (PCO) at elevated temperatures can be accommodated at room temperature if cooling is performed in relatively low oxygen partial pressures (i.e. P(O2) ~ 10-3 mbar). We use the temperature dependence of the chemical expansion in reduced PCO as a metric to explore this phenomenon.