Synergized PGM Catalyst Systems Including Platinum for TWC Application

• US 20150238941A1
• Filed: 02/24/2014
• Published: 08/27/2015
• Est. Priority Date: 11/26/2013
• Status: Active Grant

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: Clean Diesel Technologies, Inc.
• Inventors: Nazarpoor, Zahra, Golden, Stephen J.
• Granted Patent: US 9,555,400 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2255/1021 Platinum
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/1025 Rhodium
• 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 2255/9022 Two layers
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• 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 23/8986 with manganese, technetium or rhenium
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/17 Copper
• CPC Class Codes: B01J 2523/31 Aluminium
• 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 2523/824 : Palladium
• CPC Class Codes: B01J 37/0244 : Coatings comprising several layers
• CPC Class Codes: B01J 37/035 : Precipitation on carriers
• CPC Class Codes: B01J 37/038 : to form slurries or suspensions, e.g. a washcoat
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

Synergized Platinum Group Metals (SPGM) catalyst system for TWC application is disclosed. Disclosed SPGM catalyst system may include a washcoat that includes stoichiometric Cu—Mn spinel structure, supported on doped ZrO₂, and an overcoat that includes PGM, such as platinum (Pt) supported on carrier material oxides, such as alumina. SPGM catalyst system shows significant improvement in nitrogen oxide reduction performance under lean and also rich operating conditions. Additionally, disclosed SPGM catalyst system exhibits enhanced catalytic activity for carbon monoxide conversion. Furthermore, disclosed SPGM catalyst systems are found to have enhanced catalytic activity compared to PGM catalyst system, showing that there is a synergistic effect between PGM catalyst, such as Pt, and Cu—Mn spinel within disclosed SPGM catalyst system, which help in activity and thermal stability of disclosed SPGM catalyst.

Claims

1. A synergized platinum group metal (SPGM) catalyst system, comprising:

at least one substrate;

at least one washcoat comprising at least one oxygen storage material further comprising Cu—

Mn spinel having a niobium-zirconia support oxide; and

at least one overcoat comprising at least one platinum group metal catalyst and Al₂O₃;

wherein the at least one platinum group metal catalyst has a concentration of about 6 g/ft³ to about 1 g/ft³; and

wherein NOx conversion is higher as compared to a platinum group metal catalyst having substantially no Cu—

Mn spinel.

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

Mn spinel comprises CuMn₂O₄.

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

Mn spinel is stoichiometric.

4. The catalyst system of claim 1, wherein the niobium-zirconia support oxide comprises Nb₂O₅—

ZrO₂.

5. The catalyst system of claim 1, further comprising at least one impregnation layer.

6. The catalyst system of claim 1, wherein the at least one substrate comprises a ceramic.

7. The catalyst system of claim 1, wherein the conversion of NO_x is substantially complete under lean exhaust conditions.

8. The catalyst system of claim 1, wherein the conversion of CO is substantially complete under lean exhaust conditions.

9. The catalyst system of claim 1, wherein the conversion of NO_x is about 91% under lean exhaust conditions.

10. The catalyst system of claim 1, wherein the NO_x R-value is about 0.950.

11. The catalyst system of claim 1, wherein the NO_x R-value is about 1.0

12. The catalyst system of claim 1, wherein the niobium-zirconia support oxide comprises about 15% to about 30% by weight Nb₂O₅.

13. The catalyst system of claim 1, wherein the niobium-zirconia support oxide comprises about 25% by weight Nb₂O₅.

14. The catalyst system of claim 1, wherein the niobium-zirconia support oxide comprises about 70% to about 85% ZrO₂.

15. The catalyst system of claim 1, wherein the niobium-zirconia support oxide comprises about 75% ZrO₂.