Influence of Base Metal Loadings on TWC Performance of ZPGM Catalysts

• US 20150105242A1
• Filed: 10/31/2014
• Published: 04/16/2015
• Est. Priority Date: 03/22/2013
• Status: Abandoned Application

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: Clean Diesel Technologies, Inc.
• Inventors: Nazarpoor, Zahra, Golden, Stephen J.
• Application Number:
  US14/530,347
• Publication Number:
  US 20150105242A1
• Time in Patent Office: Days
• US Class Current: 502/302
• 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 2255/405 Spinels
• CPC Class Codes: B01D 2255/65 Catalysts not containing noble metals
• 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 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/005 Spinels
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y10S 502/52712 Plural layers on a support, each layer having a distinct function

Abstract

Influence of a plurality of base metal loadings on TWC performance 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 to evaluate the influence of variations of base metal loadings on TWC performance in NO_X conversion. As a result of increasing Cu—Mn base metal loadings, improvements of lean NO_X conversion and oxygen storage capacity may be realized at higher base metal loading ratios. The ZPGM catalyst samples exhibiting higher NO_X conversion and OSC are compared with commercial PGM catalyst samples under lean condition. OSC isothermal oscillating tests are carried out to confirm the increase in OSC property of samples, as well as TWC performance, both correlated to increasing base metal loadings that may further improve TWC performance.

Claims

1. A catalytic system, comprising:

a substrate;

a washcoat applied to said substrate comprising alumina;

an overcoat applied to said washcoat comprising at least one support oxide comprising doped ZrO₂ and at least one impregnation layer of Cu—

Mn spinel; and

at least one catalyst applied to the at least one support oxide;

wherein the at least one catalyst is substantially free of platinum group metals.

2. The catalyst system of claim 1, wherein the doped ZrO₂ comprises ZrO₂—

Pr₆O₁₁.

3. The catalyst system of claim 1, wherein the Cu—

Mn spinel had a general formula of Cu_1.0Mn_2.0O₄.

4. The catalyst system of claim 1, wherein the Cu—

Mn spinel comprises about 8.9% by weight Cu and about 15.3% by weight Mn.

5. The catalyst system of claim 4, wherein the oxygen storage capacity is higher than a standard platinum group metal catalyst.

6. The catalyst system of claim 4, wherein the O₂ delay time is about 46.00 seconds.

7. The catalyst system of claim 1, wherein the Cu—

Mn spinel comprises about 11.8% by weight Cu and about 20.4% by weight Mn.

8. The catalyst system of claim 1, wherein the Cu—

Mn spinel comprises about 14.8% by weight Cu and about 25.5% by weight Mn.

9. The catalyst system of claim 1, wherein the Cu—

Mn spinel comprises about 17.7% by weight Cu and about 30.6% by weight Mn.

10. The catalyst system of claim 1, wherein the Cu—

Mn spinel comprises about 23.6% by weight Cu and about 40.8% by weight Mn.

11. The catalyst system of claim 10, wherein the oxygen storage capacity is higher than a standard platinum group metal catalyst.

12. The catalyst system of claim 10, wherein the O₂ delay time is greater than 135 seconds.

13. The catalyst system of claim 1, wherein the substrate comprises ceramics.

14. The catalyst system of claim 1, wherein the conversion of NO_x increases with an increasing amount of Cu—

Mn spinel.

15. The catalyst system of claim 1, wherein the NO/CO cross over increases with an increasing amount of Cu—

Mn spinel.

16. The catalyst system of claim 1, wherein the catalytic performance under lean conditions increases with an increasing amount of Cu—

Mn spinel.

17. The catalyst system of claim 1, wherein engine performance under lean conditions increases with an increasing amount of Cu—

Mn spinel.

18. The catalyst system of claim 1, wherein the CO delay time is greater than 120 seconds.