Nonstoichiometry and Defect Chemistry in Praseodymium-Cerium Oxide

Abstract

Praseodymium cerium oxide (Pr _x Ce_{1 − x}O_{2 − δ}) is a mixed ionic-electronic conductor with high levels of nonstoichiometry under oxidizing conditions resulting from reduction of Pr^{4 +} to Pr^{3 +}. Coulometric titration measurements performed on (Pr _x Ce_{1 − x}O_{2 − δ}) 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.