Method of producing gas cleaning catalyst unit

• US 20100267547A1
• Filed: 04/14/2010
• Published: 10/21/2010
• Est. Priority Date: 04/16/2009
• Status: Abandoned Application

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yotou, Hiroaki
• Application Number:
  US12/798,921
• Publication Number:
  US 20100267547A1
• Time in Patent Office: Days
• US Class Current: 502/5
• CPC Class Codes: B01D 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/42 Platinum
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 23/58 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 23/63 with rare earths or actinides
• CPC Class Codes: B01J 23/78 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 23/83 with rare earths or actinides
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B01J 35/612 less than 10 m2/g
• CPC Class Codes: B01J 35/613 10-100 m2/g
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: B01J 37/0242 Coating followed by impregnation
• CPC Class Codes: B01J 37/035 Precipitation on carriers
• CPC Class Codes: B01J 37/16 Reducing
• CPC Class Codes: B01J 37/343 of ultrasonic wave energy
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

In a method of producing a gas cleaning catalyst unit, a supporting layer is formed on a surface of a base member. The supporting layer is made of metal oxide. A catalyst slurry is formed by making catalyst component to be suspended in a solvent. The base member having the supporting layer is immersed in the catalyst slurry. Ultrasonic wave is radiated to the base member immersed in the catalyst slurry, such that the catalyst component is supported on the supporting layer.

Claims

1. A method of producing a gas cleaning catalyst unit comprising:

forming a supporting layer made of metal oxide on a surface of a base member;

forming a catalyst slurry by making catalyst component to be suspended in a solvent;

immersing the base member having the supporting layer in the catalyst slurry; and

radiating ultrasonic wave to the base member immersed in the catalyst slurry, such that the catalyst component is supported on the supporting layer.

2. The producing method according to claim 1, wherein the forming of the supporting layer includes:

forming a support slurry by making support particles made of the metal oxide to be suspended in a solvent,;

immersing the base member in the support slurry; and

firing the base member after the base member is immersed in the support slurry.

3. The producing method according to claim 2, wherein

the firing of the base member is performed at a temperature equal to or higher than 800°

C.

4. The producing method according to claim 1, wherein

the forming of the supporting layer is performed in a manner that the supporting layer has a surface area equal to or smaller than 50 m²/g.

5. The producing method according to claim 1, wherein

the metal oxide defining the supporting layer is an oxide of at least one element selected from Mg, Al, Si, Ca, Sr, Ba, Sc, Ti, Fe, Y, Zr, Nb, Bi, Pr, La, Ce and Nd, or is a solid solution having at least two elements selected from Mg, Al, Si, Ca, Sr, Ba, Sc, Ti, Fe, Y, Zr, Nb, Bi, Pr, La, Ce and Nd.

6. The producing method according to claim 1, wherein

the catalyst component is made of transition metal or transition metal oxide having an oxidizing or reducing ability relative to HC, CO and NOx.

7. The producing method according to claim 1, wherein

the catalyst component is made of metal oxide, metal salt, organometallic complex, or catalyst precursor made of a derivative of the metal oxide, the metal salt, or the organometallic complex,

the catalyst slurry has the catalyst precursor dispersed in the solvent, and

the solvent is made of alcohol.

8. The producing method according to claim 1, wherein

the catalyst component is made of metal oxide, metal salt, organometallic complex, or catalyst precursor made of a derivative of the metal oxide, the metal salt, or the organometallic complex,

the catalyst slurry has the catalyst precursor in the solvent, and

the catalyst slurry further has a reducing agent to reduce a metal ion of the catalyst precursor.

9. The producing method according to claim 8, wherein

the reducing agent is made of at least one of amine, sugar, aldehyde, carboxylic acid, or polymer surface-active agent.

10. The producing method according to claim 8, wherein

the reducing agent is added into the catalyst slurry at a concentration of 0.01-10 wt %.

11. The producing method according to claim 1, wherein the radiating of ultrasonic wave is performed with a frequency range 20-300 kHz.

12. The producing method according to claim 1, further comprising:

forming a promoter slurry by dispersing promoter particle in a solvent, before the base member is immersed in the catalyst slurry;

immersing the base metal having the supporting layer in the promoter slurry; and

heating the base metal immersed in the promoter slurry, such that the promoter particle is supported on the supporting layer, wherein

the promoter particle is made of an oxide of element selected from Ce, Zr, La, Y, Fe, Bi, Pr, Mg and Nb, or is made of a solid solution having at least two elements selected from Ce, Zr, La, Y, Fe, Bi, Pr, Ti, Mg and Nb.

13. The producing method according to claim 1, wherein

the base member is made of a honeycomb structure,

the honeycomb structure includes a porous wall having a polygon grid shape,

the wall defines plural cells in the honeycomb structure, and

the cell extends in an axis direction of the honeycomb structure.