Optimization of Washcoat Adhesion of Zero-PGM Catalyst on Metallic Substrates

• US 20150005158A1
• Filed: 06/26/2013
• Published: 01/01/2015
• Est. Priority Date: 06/26/2013
• Status: Active Grant

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: CDTI
• Inventors: Nazarpoor, Zahra, Kitazumi, Sen, Ngo, Johnny T.
• Granted Patent: US 9,517,449 B2
• Time in Patent Office: Days
• US Class Current: 502/304
• CPC Class Codes: B01D 2255/206 Rare earth metals
• CPC Class Codes: B01D 2255/207 Transition metals
• CPC Class Codes: B01D 2255/65 Catalysts not containing noble metals
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• 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: B01J 23/72 Copper
• 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 35/394 Metal dispersion value, e.g. percentage or fraction
• 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 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B01J 37/0036 Grinding
• CPC Class Codes: B01J 37/0225 of metal substrates
• CPC Class Codes: B01J 37/03 Precipitation; Co-precipitation

Abstract

Solutions to the problem of washcoat and/or overcoat adhesion loss of ZPGM catalyst on metallic substrates are disclosed. Present disclosure provides a novel process for improving WCA to metallic substrates of ZPGM catalyst systems. Reduction of WCA loss and improved catalyst activity may be enabled by the selection of processing parameters determined from variations of pH and addition of binder to overcoat slurry, and particle size of washcoat. Processing parameters may be applied to a plurality of metallic substrates of different geometries and cell densities.

Claims

1. A method for improving adhesion of a chemical composition, the method comprising:

providing at least one substrate;

adjusting a pH of at least one chemical slurry suitable for deposition on the substrate and comprising at least one ZPGM catalyst;

adjusting a particle size of the at least one chemical slurry; and

depositing the at least one chemical slurry on the substrate.

2. The method according to claim 1, wherein the substrate comprises about 300 to about 400 cells per square inch.

3. The method according to claim 1, wherein the substrate is metallic.

4. The method according to claim 1, wherein the pH of the chemical slurry is about 4.0 to about 6.8.

5. The method according to claim 1, wherein the pH of the chemical slurry is about 5.0 to about 6.0.

6. The method according to claim 1, wherein the average particle size of the slurry about 6.0 to about 7.0 μ

m.

7. The method according to claim 1, wherein at least one portion of the slurry has a particle size selected from the group consisting of 4.5 μ

m, 5.6 μ

m, and 7.0 μ

m.

8. The method according to claim 1, wherein the chemical slurry further comprises at least one support oxide and at least one oxygen storage material.

9. The method according to claim 1, wherein the chemical slurry further comprises one selected from the group consisting of copper oxide, cerium oxide, and a combination thereof.

10. The method according to claim 1, wherein the at least one ZPGM catalyst is prepared by one selected from the group consisting of using co-milling, co-precipitation, and combination thereof.

11. The method according to claim 1, wherein the chemical slurry further comprises at least one binder.

12. The method according to claim 11, wherein the least one binder comprises alumina.

13. The method according to claim 11, wherein loss of deposited chemical slurry is less than about 3%.

14. The method according to claim 13, wherein the pH is about 6.8, and the particle size of the chemical slurry is about 5.6 to about 7.0 μ

m.

15. The method according to claim 11, wherein the T50 of hydrocarbons is about 315°

C.

16. The method according to claim 1, wherein loss of deposited chemical slurry is reduced by increasing the particle size of the chemical slurry.

17. The method according to claim 1, wherein loss of deposited chemical slurry is reduced by increasing the particle size of the chemical slurry.