Nonstoichiometry and defect chemistry in praseodymium-cerium oxide

Praseodymium cerium oxide (PrxCe1-xO2-delta) is a mixed ionic-electronic conductor with high levels of nonstoichiometry under oxidizing conditions resulting from reduction of Pr4+ to Pr3+. Coulometric titration measurements performed on (PrxCe1-xO2-delta) with x = 0.2 are generally consistent with those derived from electrical conductivity measurements. Nevertheless, a somewhat larger degree of nonstoichiometry measured via coulometric titration implies that non-charged defect species may be significant in the system.