| 摘要 |
PROBLEM TO BE SOLVED: To produce a cerium-zirconium compound oxide having <=400 deg.C oxygen absorbing and releasing temperature even after repetitively carrying out oxidizing and reducing treatments at 1,000 deg.C and having >=500μmol/g amount of released oxygen expressed in terms of oxygen molecule. SOLUTION: A complex salt precipitate obtained by adding a reducing precipitant to a solution containing cerium and zirconium ions is aged and the resultant cerium-zirconium compound hydroxide containing trivalent cerium is baked in an inert or a nonoxidizing atmosphere to afford a cerium-zirconium compound oxide containing the trivalent cerium. The obtained compound oxide is then subjected to surface modification with a surface treating agent such as a metal halide, an alkali halide, an acid, an alkali or a halogen-containing organic compound. The cerium is compounded with the zirconium so as to provide (1/99) to (99/1) molar ratio of the cerium to zirconium in the cerium-containing compound oxide. The reducing precipitant is hydrazine. The surface treating agent is ammonium chloride.
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