Optimum Loading of Copper-Manganese Spinel on TWC Performance and Stability of ZPGM Catalyst Systems

• US 20150018205A1
• Filed: 06/18/2014
• Published: 01/15/2015
• Est. Priority Date: 07/12/2013
• Status: Abandoned Application

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: Clean Diesel Technologies, Inc.
• Inventors: Nazarpoor, Zahra, Golden, Stephen J.
• Application Number:
  US14/308,401
• Publication Number:
  US 20150018205A1
• Time in Patent Office: Days
• US Class Current: 502/324
• CPC Class Codes: B01D 2255/20715 Zirconium
• CPC Class Codes: B01D 2255/2073 Manganese
• CPC Class Codes: B01D 2255/20761 Copper
• CPC Class Codes: B01D 2255/2092 Aluminium
• CPC Class Codes: B01D 2255/405 Spinels
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• CPC Class Codes: B01D 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/005 Spinels
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: Y02C 20/10 of nitrous oxide (N2O)
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Influence of a plurality of base metal loadings on TWC performance and thermal stability of ZPGM catalysts for TWC applications is disclosed. ZPGM catalyst samples are prepared and configured with washcoat on ceramic substrate, overcoat including doped Zirconia support oxide, and impregnation layer of Cu—Mn spinel with different base metal loadings. Testing of ZPGM catalyst samples including variations of base metal loadings is developed under isothermal steady state sweep test condition for fresh and aged ZPGM catalysts to evaluate the influence of variations of base metal loadings on TWC performance specially NO_x conversions and level of stability of NOx conversion. As a result disclosed ZPGM catalyst systems with an optimum base metal loadings exhibit high and stable NOx conversion which is suitable for under floor TWC application.

Claims

1. A method for optimizing a catalytic system, comprising:

providing a catalyst system, comprising;

a substrate;

a washcoat suitable for deposition on the substrate, comprising alumina;

an overcoat suitable for deposition on the substrate, the overcoat comprising at least one support oxide material comprising ZrO₂; and

an impregnation layer suitable for deposition on the substrate, comprising copper-manganese spinel having a compositional ratio of X, wherein X comprises between 10 and 15 percent by weight copper and 15 to 25 percent by weight of manganese; and

adjusting the ratio of copper to manganese to improve NO_x conversion.

2. The method according to claim 1, wherein the copper to manganese ratio is about 11.8% to about 20.4%.

3. The method according to claim 1, wherein the copper-manganese spinel has the general formula of Cu_xMn_3-xO₄.

4. The method according to claim 1, wherein the catalytic system is hydrothermal aging at greater than 800°

C.

5. The method according to claim 4, wherein the hydrothermal aging lasts for about 2 to about 6 hours.

6. The method according to claim 4, wherein the hydrothermal aging lasts for about 4 hours.

7. The method according to claim 1, wherein the overcoat further comprises at least one oxygen storage material.

8. The method according to claim 1, wherein X is selected from the range of 1×

to 5×

.

9. The method according to claim 1, wherein the NO/CO cross over R-value is 1.05.

10. The method according to claim 1, wherein the NO conversion is greater than 90% at an R-value of 1.0.

11. The method according to claim 1, wherein the NO conversion is greater than 99% at an R-value of 1.0.

12. The method according to claim 1, wherein the CO conversion is greater than 90% at an R-value of 1.0.

13. The method according to claim 1, wherein the CO conversion is greater than 99% at an R-value of 1.0.

14. The method according to claim 4, wherein the NO/CO cross over value R-value is 1.16.

15. The method of claim 1, wherein the catalyst system is hydrothermal aged at 800°

C. for greater than 15 hours.

16. The method of claim 15, wherein X is 3×

.

17. The method of claim 1, wherein the conversion of NO_x increases as the value of X increases in the range of 1×

to 5×

.