WASTE GAS PURIFICATION CATALYST AND MANUFACTURE THEREOF

Japanese Patent JP3644572

B2

PROBLEM TO BE SOLVED: To suppress agglomeration of Rh at the time of oxidation and reduction treatment by depositing rhodium on a carrier comprising α-alumina and exposing a specified quantity or more of deposition quantity of the rhodium as fine particles having particle sizes not larger than a specified particles size on a surface of the carrier.
SOLUTION: A carrier having a cover layer 2 comprising amorphous alumina and transition alumina and formed on a surface of α alumina particles 1 is impregnated with and made to deposite rhodium to constitute a Rh carrier. The Rh carrier is subjected to heat treatment at 800°C in air for 3 hours so as to dissolve in solid solution the carried Rh to the cover layer 20 and an Rh solid solution carrier is obtained. The Rh solid solution carrier is subject to heat treatment in nitrogen gas containing 10% of hydrogen gas in a reducing atmosphere at 1000°C for one hour and 80% of rhodium with respect to deposition quantity that has been dissolved in solid solution is precipitated as fine particles having particles sizes not larger than 5 mm and a catalyst having a cover layer 21 of crystalline α alumina Rh particles 3 is obtained. By such a constitution, agglomeration of the Rh at the time of oxidation and reduction treatment is suppressed.

Kimura Norio
Akihiko Suda
Terao Naohiro
Satoko Matsuoka
Suzuki Companion
Hideo Sofukawa

JP33737297A

April 27, 2005

December 08, 1997

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Toyota Central R & D Labs.

B01J23/46; B01D53/94; (IPC1-7): B01J23/46; B01D53/94

JP9299796A
JP57087837A
JP55041894A

Hiroshi Okawa

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