A composite oxide having oxygen absorption and release capabilities, comprising cerium, zirconium, and hafnium in a total amount of 90 to 100 wt.% based on the total amount of metals, the contents of cerium, zirconium, and hafnium being respectively 14.0 to 70.5 at %, 29.49 to 72.5 at %, and 0.01 to 13.5 at % based on the total amount of the cerium, zirconium, and hafnium, having a solubility of at least 70 %, and exhibiting, when held in a reducing atmosphere at a temperature of 600 °C, such a reducibility that at least 90 % of the tetravalent cerium contained in the composite oxide is reduced to trivalent cerium; and a process for preparing a composite oxide by preparing a composite salt precipitate from the starting material solution wherein at least 85 % of cerium ions are Ce?4+¿ by coprecipitation and subjecting the precipitate to particular firing involving reductive firing.

Title
Composite oxide having oxygen absorption and release capabilities and process for preparing the same
Application Number
PCT/JP1997/001173
Publication Number
1997/037933
Application Date
April 4, 1997
Publication Date
October 16, 1997
Inventor
Takemori Hirofumi
Fujiwara Kazuhito
Murota Tadatoshi
Yokoi Hideo
Agent
SAKAI Hajime
Assignee
Takemori Hirofumi
Fujiwara Kazuhito
Murota Tadatoshi
Yokoi Hideo
Santoku Metal
IPC
C01G 27/00
C01G 25/00
C01B 13/02
B01J 23/10
B01J 20/06
View Original Source