Exhaust gas-purifying catalyst

• US 8,741,799 B2
• Filed: 11/28/2011
• Issued: 06/03/2014
• Est. Priority Date: 05/27/2009
• Status: Active Grant

• Current Assignee: Cataler Corporation (Toyota Motor Corporation)
• Original Assignee: Cataler Corporation (Toyota Motor Corporation)
• Inventors: Matsueda, Satoshi, Hirai, Akimasa, Taki, Kenichi, Yabuzaki, Yuji
• Primary Examiner(s): Li, Jun
• Application Number:
  US13/305,255
• Publication Number:
  US 20120071318A1
• Time in Patent Office: 918 Days
• Field of Search: 502/325, 502/339, 502/170, 502/217
• US Class Current: 502/170
• CPC Class Codes: B01D 2255/1021 Platinum
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/1025 Rhodium
• CPC Class Codes: B01D 2255/204 Alkaline earth metals
• CPC Class Codes: B01D 2255/2042 Barium
• CPC Class Codes: B01D 2255/2092 Aluminium
• CPC Class Codes: B01D 2255/407 Zr-Ce mixed oxides
• CPC Class Codes: B01D 2255/9022 Two layers
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• CPC Class Codes: B01D 2255/9202 Linear dimensions
• CPC Class Codes: B01D 53/944 Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts three-way-catalysts [TWC] B01D53/9445
• CPC Class Codes: B01D 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/58 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 27/053 Sulfates
• CPC Class Codes: B01J 31/26 containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: B01J 37/0219 the coating containing organic compounds
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: F01N 2370/02 used in catalytic reactors
• CPC Class Codes: F01N 2510/06 : for exhaust purification, e.g. catalytic reaction
• CPC Class Codes: F01N 2510/0684 : having more than one coating layer, e.g. multi-layered coatings
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

An exhaust gas-purifying catalyst includes a substrate, and a catalytic layer facing the substrate and including a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μm, the average particle diameter being obtained by observation using a scanning electron microscope. Another exhaust gas-purifying catalyst includes a substrate, and a catalytic layer formed on the substrate using slurry containing a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μm, the average particle diameter being obtained by observation using a scanning electron microscope.

Claims

1. An exhaust gas-purifying catalyst comprising:

a substrate; and

a catalytic layer facing the substrate and including a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μ

m, the average particle diameter being obtained by observation using a scanning electron microscope,

wherein the oxygen storage material is a composite oxide containing cerium and zirconium; and

the catalytic layer having a correlation coefficient ρ

_PM,AE of 0.60 or more, the coefficient ρ

_PM,AE being expressed by the following formula (7);

2. The exhaust gas-purifying catalyst according to claim 1, wherein the average particle diameter falls within a range of 0.05 to 0.40 μ

m.

3. The exhaust gas-purifying catalyst according to claim 1, wherein the catalytic layer has a correlation coefficient ρ

_Al,AE of 0.60 or more, the coefficient ρ

_Al,AE being expressed by the following formula (1);

4. The exhaust gas-purifying catalyst according to claim 1, wherein the alkaline earth metal is barium.

5. The exhaust gas-purifying catalyst according to claim 1, wherein the precious metal is at least one selected from the group consisting of palladium, platinum, rhodium, and a combination of two or more of them.

6. An exhaust gas-purifying catalyst comprising:

a substrate; and

a catalytic layer formed on the substrate using slurry containing a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μ

m, the average particle diameter being obtained by observation using a scanning electron microscope, the catalytic layer having a correlation coefficient ρ

_PM,AE of 0.60 or more, the coefficient ρ

_PM,AE being expressed by the following formula (7);

7. The exhaust gas-purifying catalyst according to claim 6, wherein the slurry further contains citric acid.

8. The exhaust gas-purifying catalyst according to claim 6, wherein the alkaline-earth metal is barium.

9. An exhaust gas-purifying catalyst comprising:

a substrate; and

a catalytic layer facing the substrate and including a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μ

m, the average particle diameter being obtained by observation using a scanning electron microscope, the catalytic layer having a correlation coefficient ρ

_Al,AE of 0.60 or more, the coefficient ρ

_Al,AE being expressed by the following formula (1);

10. The exhaust gas-purifying catalyst according to claim 9, wherein the alkaline-earth metal is barium.