Patent attributes
To provide a method for industrially efficiently producing an exhaust gas purifying catalyst containing a perovskite-type composite oxide which is stable and has a less reduced specific surface area and is also effectively prevented from decreasing in its catalytic performance even in endurance in high temperature oxidative reducing atmospheres, a pre-crystallization composition containing elementary components constituting a perovskite-type composite oxide containing a noble metal is prepared, is mixed with a powder of theta-alumina and/or alpha-alumina to prepare a mixture, and the mixture is heat treated. Thus, the resulting perovskite-type composite oxide supported by the powder of theta-alumina and/or alpha-alumina can keep its thermostability at a sufficient level thereby to effectively prevent the catalytic performance from decreasing. This method can industrially efficiently produce the exhaust gas purifying catalyst.
