Synergized PGM Catalyst with Low PGM Loading and High Sulfur Resistance for Diesel Oxidation Application

• US 20160136617A1
• Filed: 11/17/2014
• Published: 05/19/2016
• Est. Priority Date: 11/17/2014
• Status: Abandoned Application

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: Clean Diesel Technologies, Inc.
• Inventors: Nazarpoor, Zahra, Golden, Stephen J.
• Application Number:
  US14/543,564
• Publication Number:
  US 20160136617A1
• 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 2255/2061 Yttrium
• CPC Class Codes: B01D 2255/2073 Manganese
• CPC Class Codes: B01D 2255/402 Perovskites
• CPC Class Codes: B01D 2255/9022 Two layers
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• 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 23/40 of the platinum group metals
• CPC Class Codes: B01J 23/42 Platinum
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 35/19 Catalysts containing parts with different compositions
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers

Abstract

Sulfur-resistant SPGM catalysts with significant oxidation capabilities are disclosed. Catalytic layers of SPGM samples may be prepared using incipient wetness and metallizing techniques to structure a washcoat layer of ZPGM material of YMnO₃ perovskite , and an overcoat layer including Pt/Pd composition on alumina-silica support oxide. Loading of PGM in OC layer is less than 5 g/ft³. A testing methodology for samples may be enabled including of DOC light-off, and soaking under isothermal DOC and sulfated DOC conditions to assess synergistic influence of adding ZPGM to PGM catalyst samples. Resistance to sulfur and catalytic stability may be observed under 5.2 gS/L condition to assess significant improvements in NO oxidation, HC conversion, and CO selectivity. Resistance to sulfur of disclosed SPGM catalyst may be compared with performance of an equivalent PGM control catalyst for DOC applications.

Claims

1. A diesel oxidation catalyst (DOC) system comprising:

a 2-layer synergized platinum group metal (SPGM) catalyst comprising;

a) a washcoat layer comprising zero platinum group metal (ZPGM) catalyst, optionally on a first support oxide, and

b) an overcoat layer comprising a low loading platinum group metal (LLPGM) catalyst, optionally on a second support oxide.

2. The DOC system of claim 1, wherein the washcoat layer comprises a perovskite structure.

3. The DOC system of claim 1, wherein the washcoat layer is deposited on a substrate.

4. The DOC system of claim 2, wherein the perovskite comprises silver, manganese, yttrium, lanthanum, cerium, iron, praseodymium, neodymium, strontium, cadmium, cobalt, scandium, copper, or niobium.

5. The DOC system of claim 1, wherein the first or second support oxide independently comprises zirconia, niobium pent oxide, niobium-zirconia, alumina type support oxide, titanium dioxide, tin oxide, zeolite, silicon dioxide, or mixtures thereof.

6. The DOC system of claim 5, wherein the zirconia is doped.

7. The DOC system of claim 6, wherein the doped zirconia is doped with a lanthanide group metal.

8. The DOC system of claim 1, wherein the ZPGM catalyst comprises of YMnO₃ perovskite structure on a doped ZrO₂ support oxide.

9. The DOC system of claim 1, wherein the LLPGM catalyst comprises platinum and palladium on an alumina-silica support oxide.

10. The DOC system of claim 9, wherein the alumina-silica support oxide is Al₂O₃-5% SiO₂.

11. The DOC system of claim 1, wherein the LLPGM is about 5 g/ft³.

12. The DOC system of claim 11, wherein the about 5 g/ft³ is about 4.5 g/ft³ of platinum and about 0.25 g/ft³ of palladium.

13. The DOC system of claim 1, wherein the DOC has a sulfur resistance of about 5.2 gS/L.

16. The method of claim 4, wherein about 100% of carbon monoxide and about 92% of hydrocarbon is converted.

14. The method of converting nitrogen oxides from diesel exhaust comprising applying a gas stream to a DOC system comprising a 2-layer synergized platinum group metal (SPGM) catalyst comprising:

a) a washcoat layer comprising zero platinum group metal (ZPGM) catalyst, optionally on a first support oxide, and

b) an overcoat layer comprising a low loading platinum group metal (LLPGM) catalyst, optionally on a second support oxide.

15. The method of claim 14, wherein nitrogen oxide conversion is about 50%.

17. The DOC system of claim 14, wherein the washcoat layer comprises a perovskite structure.

18. The DOC system of claim 14, wherein the washcoat layer is deposited on a substrate.

19. The DOC system of claim 17, wherein the perovskite comprises silver, manganese, yttrium, lanthanum, cerium, iron, praseodymium, neodymium, strontium, cadmium, cobalt, scandium, copper, or niobium.

20. The DOC system of claim 14, wherein the first or second support oxide independently comprises zirconia, niobium pent oxide, niobium-zirconia, alumina type support oxide, titanium dioxide, tin oxide, zeolite, silicon dioxide, or mixtures thereof.

21. The DOC system of claim 20, wherein the zirconia is doped.

22. The DOC system of claim 21, wherein the doped zirconia is doped with a lanthanide group metal.

23. The DOC system of claim 14, wherein the ZPGM catalyst comprises of YMnO₃ perovskite structure on a doped ZrO₂ support oxide.

24. The DOC system of claim 14, wherein the LLPGM catalyst comprises platinum and palladium on an alumina-silica support oxide.

25. The DOC system of claim 24, wherein the alumina-silica support oxide is Al₂O₃-5% SiO₂.

26. The DOC system of claim 14, wherein the LLPGM is about 5 g/ft³.

27. The DOC system of claim 26, wherein the about 5 g/ft³ is about 4.5 g/ft³ of platinum and about 0.25 g/ft³ of palladium.

28. The DOC system of claim 14, wherein the DOC has a sulfur resistance of about 5.2 gS/L.