Compositions for passive NOx adsorption (PNA) systems and methods of making and using same

• US 9,687,811 B2
• Filed: 03/19/2015
• Issued: 06/27/2017
• Est. Priority Date: 03/21/2014
• Status: Active Grant

• Current Assignee: Umicore AG & Company KG (Umicore S.A.)
• Original Assignee: SDC Materials,Inc.
• Inventors: Biberger, Maximilian A., Yin, Qinghua, Qi, Xiwang, Kearl, Bryant
• Primary Examiner(s): Nguyen, Cam N.
• Application Number:
  US14/663,330
• Publication Number:
  US 20150266002A1
• Time in Patent Office: 831 Days
• Field of Search: 502302-304, 502327, 502332-334, 502339, 502349, 502355, 502439, 50252719, 977773, 977775
• CPC Class Codes: B01D 2255/1021 Platinum
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/1026 Ruthenium
• CPC Class Codes: B01D 2255/2061 Yttrium
• CPC Class Codes: B01D 2255/2063 Lanthanum
• CPC Class Codes: B01D 2255/2065 Cerium
• CPC Class Codes: B01D 2255/20715 Zirconium
• CPC Class Codes: B01D 2255/91 NOx-storage component incorporated in the catalyst
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• CPC Class Codes: B01D 53/9413 Processes characterised by a specific catalyst
• CPC Class Codes: B01D 53/9481 Catalyst preceded by an adsorption device without catalytic function for temporary storage of contaminants, e.g. during cold start
• CPC Class Codes: B01J 20/02 comprising inorganic material
• CPC Class Codes: B01J 20/0207 Compounds of Sc, Y or Lanthanides
• CPC Class Codes: B01J 20/0211 Compounds of Ti, Zr, Hf
• CPC Class Codes: B01J 20/04 comprising compounds of alkali metals, alkaline earth metals or magnesium
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/28007 with size in the range 1-100 nanometers, e.g. nanosized particles, nanofibers, nanotubes, nanowires or the like carbon nanostructures B01J20/205
• CPC Class Codes: B01J 20/28045 Honeycomb or cellular structures; Solid foams or sponges
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/3295 Coatings made of particles, nanoparticles, fibers, nanofibers
• CPC Class Codes: B01J 23/42 : Platinum
• CPC Class Codes: B01J 23/63 : with rare earths or actinides
• CPC Class Codes: B01J 35/19 : Catalysts containing parts with different compositions
• CPC Class Codes: B01J 35/23 : in a colloidal state
• CPC Class Codes: B01J 35/45 : Nanoparticles
• CPC Class Codes: B01J 37/0244 : Coatings comprising several layers
• CPC Class Codes: B01J 37/0246 : Coatings comprising a zeolite
• CPC Class Codes: F01N 3/0807 : by using absorbents or adsorbents
• CPC Class Codes: F01N 3/0814 : combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0842 : Nitrogen oxides
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The present disclosure relates to a substrate containing passive NO_x adsorption (PNA) materials for treatment of gases, and washcoats for use in preparing such a substrate. Also provided are methods of preparation of the PNA materials, as well as methods of preparation of the substrate containing the PNA materials. More specifically, the present disclosure relates to a coated substrate containing PNA materials for PNA systems, useful in the treatment of exhaust gases. Also disclosed are exhaust treatment systems, and vehicles, such as diesel or gasoline vehicles, particularly light-duty diesel or gasoline vehicles, using catalytic converters and exhaust treatment systems using the coated substrates.

Claims

1. A coated substrate comprising:

a substrate; and

a Passive NOx Adsorber (PNA) layer comprising nano-sized platinum group metal (PGM) on a plurality of support particles comprising cerium oxide, wherein the amount of cerium oxide used in the PNA layer is from about 50 g/L to about 400 g/L.

2. The coated substrate of claim 1, wherein the PNA layer stores NO_x gas up to at least a first temperature and releases the stored NO_x gas at or above the first temperature.

3. The coated substrate of claim 2, wherein the first temperature is 150°

C.

4. The coated substrate of claim 1, wherein the plurality of support particles are micron-sized.

5. The coated substrate of claim 1, wherein the plurality of support particles are nano-sized.

6. The coated substrate of claim 1, wherein the plurality of support particles further comprise zirconium oxide, lanthanum oxide, yttrium oxide, or a combination thereof.

7. The coated substrate of claim 1, wherein the nano-sized PGM on the plurality of support particles is produced by wet chemistry techniques followed by calcination.

8. The coated substrate of claim 1, wherein the nano-sized PGM on the plurality of support particles is produced by incipient wetness followed by calcination.

9. The coated substrate of claim 1, wherein the nano-sized PGM on the plurality of support particles comprise composite nano-particles, wherein the composite nano-particles comprise a support-nano-particle and a PGM nano-particle.

10. The coated substrate of claim 9, wherein the composite nano-particles are bonded to micron-sized carrier particles to form nano-on-nano-on-micro particles.

11. The coated substrate of claim 10, wherein the carrier particles comprise cerium oxide, zirconium oxide, lanthanum oxide, yttrium oxide, or a combination thereof.

12. The coated substrate of claim 11, wherein the carrier particle comprises 86 wt % cerium oxide, 10 wt % zirconium oxide, and 4 wt % lanthanum oxide.

13. The coated substrate of claim 9, wherein the composite nano-particles are embedded within carrier particles to form nano-on-nano-in-micro particles.

14. The coated substrate of claim 9, wherein the composite nano-particles are plasma created.

15. The coated substrate of claim 1, wherein the PGM comprises palladium.

16. The coated substrate of claim 15, wherein the PNA layer comprises about 2 g/L to about 4 g/L palladium.

17. The coated substrate of claim 16, wherein the PNA layer comprises about 3 g/L palladium.

18. The coated substrate of claim 15, wherein the coated substrate is used in a greater than or equal to 2.5 L engine system.

19. The coated substrate of claim 1, wherein the PGM comprises ruthenium.

20. The coated substrate of claim 19, wherein the PNA layer comprises about 3 g/L to about 15 g/L ruthenium.

21. The coated substrate of claim 20, wherein the PNA layer comprises about 5 g/L to about 6 g/L ruthenium.

22. The coated substrate of claim 19, wherein the first temperature is 300°

C.

23. The coated substrate of claim 19, wherein the coated substrate is used in a less than or equal to 2.5 L engine system.

24. The coated substrate of claim 1, wherein the PNA layer comprises greater than or equal to about 150 g/L of the plurality of support particles.

25. The coated substrate of claim 1, wherein the PNA layer comprises greater than or equal to about 300 g/L of the plurality of support particles.

26. The coated substrate of claim 1, wherein the PNA layer further comprises boehmite particles.

27. The coated substrate of claim 26, wherein the nano-sized PGM on the plurality of support particles comprises 95% to 98% by weight of the mixture of the nano-sized PGM on the plurality of support particles and boehmite particles in the PNA layer.

28. The coated substrate of claim 27, wherein the boehmite particles comprise 2% to 5% by weight of the mixture of the nano-sized PGM on the plurality of support particles and boehmite particles in the PNA layer.

29. The coated substrate of claim 1, wherein the substrate comprises cordierite.

30. The coated substrate of claim 1, wherein the substrate comprises a honeycomb structure.

31. The coated substrate of claim 1, further comprising a corner-fill layer deposited directly on the substrate.

32. A washcoat composition comprising a solids content of:

95% to 98% by weight nano-sized PGM on a plurality of support particles comprising cerium oxide; and

2% to 5% by weight of boehmite particles.