Title:
CATALYST FOR PURIFICATION OF EXHAUST GAS
Document Type and Number:
Japanese Patent JP3861823
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To suppress a noble metal from growing in grains at high temperatures in a catalyst carrying the noble metal on CeO2-ZrO2 double oxide powder.
SOLUTION: The proportion CCe (wt.%) of CeO2 and the proportion CZr (wt.%) of ZrO2 on the surface of the double oxide powder satisfy the relation of 0.5≤CZr/CCe≤1.5. The noble metal is deposited on the double oxide powder by using an aqueous solution of a noble metal salt showing a lower pH than the soaking pH of the double oxide powder suspended in pure water. Growth of the noble metal particles carried is suppressed under the conditions that the surface composition of the double oxide powder satisfies the relation of 0.5≤CZr/CCe≤1.5 and that the noble metal is deposited by using an aqueous solution of the noble metal salt showing the lower pH than the soaking pH.
Inventors:
Keiji Miyake
Application Number:
JP2003033839A
Publication Date:
December 27, 2006
Filing Date:
February 12, 2003
Export Citation:
Assignee:
TOYOTA JIDOSHA KABUSHIKI KAISHA
International Classes:
B01D53/94; B01J23/63; B01D53/86; (IPC1-7): B01J23/63; B01D53/86; B01D53/94
Domestic Patent References:
| JP8057316A | ||||
| JP6210175A |
Attorney, Agent or Firm:
Hiroshi Okawa
Previous Patent: CONTROL DEVICE OF HYBRID VEHICLE
Next Patent: DEVICE AND METHOD FOR REGULATING CIRCUMFERENTIAL LENGTH OF ENDLESS METAL RING
Next Patent: DEVICE AND METHOD FOR REGULATING CIRCUMFERENTIAL LENGTH OF ENDLESS METAL RING