| abstract |
A production method comprising: adding a hydroxycarboxylic acid to an aqueous solution containing a Ce salt, a Zr salt, an Al salt, and at least one selected from a La salt, an Mg salt, and a Ca salt, to produce a gel, heating the gel to obtain a solid product by decomposition of the salts, firing the solid product to obtain a fired product containing a ceria-zirconia-based regular array phase precursor and an aluminate-based composite oxide precursor, performing a reducing heat treatment of the fired product to obtain a first composite having mutually dispersed therein a pyrochlore phase and an aluminate-based composite oxide, and performing an oxidizing heat treatment of the first composite to obtain a second composite in which at least part of the pyrochlore phase is transformed into a κ phase; and an oxygen storage material having mutually dispersed therein the composite oxide and the regular array phase. |