Oxygen Nonstoichiometry and Transport Properties of Mixed-Conducting Ce0.6–xLa0.4PrxO2–δ

Abstract

The oxygen nonstoichiometry and electrical conductivity of fluorite-type solid solutions Ce_0.6‒xLa_0.4Pr_xO_2–δ (x = 0.1–0.2) were studied in the oxygen partial pressure range 10^–19–0.35 atm at 1023–1223 K. It was confirmed that the Pr^4+/3+ and Ce^4+/3+ redox pairs, which determine the concentration of p- and n-type electron charge carriers, play the dominant roles under oxidizing and reducing conditions, respectively. The conductivity vs. charge carrier concentration dependencies in these conditions are almost linear. Increasing praseodymium content leads to a substantially higher hole conductivity and an expanded range of the oxygen nonstoichiometry variations at high oxygen partial pressures. Under reducing conditions when praseodymium cations become trivalent opposite trends are observed on doping.