Optimal Composition of Copper-Manganese Spinel in ZPGM Catalyst for TWC Applications

• US 20140271387A1
• Filed: 12/05/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Abandoned Application

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: CDTI
• Inventors: Nazarpoor, Zahra
• Application Number:
  US14/097,871
• Publication Number:
  US 20140271387A1
• Time in Patent Office: Days
• US Class Current: 422/170
• CPC Class Codes: B01D 2255/207 Transition metals
• 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 53/94 by catalytic processes
• 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: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/17 Copper
• CPC Class Codes: B01J 2523/48 Zirconium
• CPC Class Codes: B01J 2523/56 Niobium
• CPC Class Codes: B01J 2523/72 Manganese
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

It is an object of the present disclosure, to provide an optimized catalyst composition with variations of Cu and Mn molar ratio, which may include a formulation Cu_xMn_3-xO₄ spinel, with a plurality of molar ratio variations for selecting the optimal Cu—Mn molar ratio for TWC application. The formulation may include a support oxide, such as Nb₂O₅—ZrO₂. Employing this optimized Cu and Mn ratio in spinel as overcoat may achieve optimal NO conversion, high catalyst activity, and enhanced thermal stability, having a chemical composition substantially free from PGM and rare earth metals. According to principles of the present disclosure, the disclosed Cu—Mn spinel on Nb—Zr support oxide for TWC applications may require a washcoat of alumina, and overcoat of Cu—Mn spinel on Nb—Zr support oxide.

Claims

1. A catalyst system, comprising:

at least one substrate;

at least one first coating applied to the at least one substrate comprising at least one oxygen storage material; and

wherein the at least one oxygen storage material comprises Cu—

Mn spinel having a niobium-zirconia support oxide; and

wherein the Cu—

Mn spinel has a general formula of Cu_xMn_3-xO₄, wherein the Cu molar ratio is from about x=0.5 to about x=1.0.

2. The catalyst system of claim 1, further comprising at least one second coating comprising Al₂O₃.

3. The catalyst system of claim 1, wherein the at least one first coating is substantially free of platinum group metals.

4. The catalyst system of claim 1, wherein the at least one first coating is substantially free of rare earth metals.

5. The catalyst system of claim 1, wherein the at least one first coating is a washcoat.

6. The catalyst system of claim 1, wherein the conversion of NO increases as x increases.

7. The catalyst system of claim 1, wherein x is 0.75.

8. The catalyst system of claim 1, wherein the T50 of NO is less than 435°

C.

9. The catalyst system of claim 1, wherein the T50 of NO is 445°

C.

10. The catalyst system of claim 1, wherein rein the at least one oxygen storage material is aged at about 900°

C.

11. The catalyst system of claim 1, wherein the at least one oxygen storage material is aged at about 1000°

C.

12. The catalyst system of claim 1, wherein CO conversion that occurs under isothermal oscillating conditions.

13. A catalyst system for use during an urban drive cycle, the catalyst system comprising:

at least one close-couple converter; and

at least one underfloor converter;

wherein the underfloor converter comprises a catalyst system, comprising;

a substrate; and

a washcoat suitable for deposition on the substrate, comprising at least one oxygen storage material and alumina;

wherein the at least one oxygen storage material comprises Cu—

Mn spinel having a niobium-zirconia support oxide; and

wherein the Cu—

Mn spinel has a general formula of Cu_xMn_3-xO₄, wherein the Cu molar ratio is from about x=0.5 to about x=1.0.

14. The catalyst system of claim 13, wherein the washcoat is substantially free of platinum group metals.

15. The catalyst system of claim 13, wherein the washcoat is substantially free of rare earth metals.

16. The catalyst system of claim 13, wherein the conversion of NO increases as x increases.

17. The catalyst system of claim 13, wherein x is 0.75.

18. The catalyst system of claim 13, wherein the T50 of NO is less than 435°

C.

19. The catalyst system of claim 13, wherein the T50 of NO is 445°

C.

20. The catalyst system of claim 13, wherein rein the at least one oxygen storage material is aged at about 900°

C.

21. The catalyst system of claim 13, wherein the at least one oxygen storage material is aged at about 1000°

C.

22. The catalyst system of claim 13, wherein CO conversion that occurs under isothermal oscillating conditions.