Abstract

Zr_0.10(Ce_1 − xPr_x)_0.90O₂ mixed oxides (x between 0 and 0.75) were prepared by coprecipitation (nitrates) or by the sol–gel route. Zirconium n-propoxide and cerium and/or praseodymium nitrates were used as precursors. “Sol–gel” oxides calcined at 900 °C were shown to be cubic with a fluorite-type structure. Coprecipated oxides could not be obtained as solid solutions. The BET surface area of these samples rapidly decreases when x > 0.50. A Raman study confirmed that all oxides were cubic and evidenced the presence of oxygen vacancies. The optimum oxygen storage capacity (OSC) was obtained for Zr_0.10(Ce_0.50Pr_0.50)_0.90O₂. It appears that the substitution of cerium by praseodymium in Zr_0.10Ce_0.90O₂ mixed oxides leads to a material with improved redox properties. The presence of vacancies, associated with Pr³⁺/Pr⁴⁺ ions, is thought to be responsible for these enhanced OSCs.