Systems and Methods for Using Pd1+ in a TWC

• US 20140364303A1
• Filed: 06/06/2013
• Published: 12/11/2014
• Est. Priority Date: 06/06/2013
• Status: Active Grant

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: CDTI
• Inventors: Hatfield, Randal L.
• Granted Patent: US 9,216,410 B2
• Time in Patent Office: Days
• US Class Current: 502/73
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/2045 Calcium
• CPC Class Codes: B01D 2255/2063 Lanthanum
• CPC Class Codes: B01D 2255/20707 Titanium
• CPC Class Codes: B01D 2255/20715 Zirconium
• CPC Class Codes: B01D 2255/20723 Vanadium
• CPC Class Codes: B01D 2255/2073 Manganese
• CPC Class Codes: B01D 2255/20738 Iron
• CPC Class Codes: B01D 2255/20776 Tungsten
• CPC Class Codes: B01D 2255/20784 Chromium
• CPC Class Codes: B01D 2255/402 Perovskites
• 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 23/002 Mixed oxides other than spinels, e.g. perovskite
• CPC Class Codes: B01J 23/62 with gallium, indium, thallium, germanium, tin or lead
• CPC Class Codes: B01J 23/6484 Niobium
• CPC Class Codes: B01J 23/6522 Chromium
• CPC Class Codes: B01J 23/6562 Manganese
• CPC Class Codes: B01J 23/8913 Cobalt and noble metals
• CPC Class Codes: B01J 2523/00 Constitutive chemical elements of heterogeneous catalysts
• CPC Class Codes: B01J 2523/23 : Calcium
• CPC Class Codes: B01J 2523/47 : Titanium
• CPC Class Codes: B01J 2523/56 : Niobium
• CPC Class Codes: B01J 2523/824 : Palladium
• CPC Class Codes: B01J 37/0215 : Coating
• CPC Class Codes: B01J 37/0244 : Coatings comprising several layers
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

Stabilized palladium (+1) compounds to mimic rhodium'"'"'s electronic configuration and catalytic properties are disclosed. Palladium (+1) compounds may be stabilized in perovskite or delafossite structures and may be employed in Three-Way Catalysts (TWC) for at least the conversion of HC, CO and NOx, in exhaust gases. The TWC may include a substrate, a wash-coat and, a first impregnation layer, a second impregnation layer and an over-coat. The second impregnation layer and the over-coat may include palladium (+1) based compounds as catalyst.

Claims

1. A catalyst system, comprising:

a substrate; and

a washcoat suitable for deposition on the substrate, comprising at least one oxide solid selected from the group consisting of at least one carrier metal oxide, and at least one catalyst; and

wherein the at least one catalyst comprises at least one perovskite structured compound having the formula ABO₃ wherein A is selected from the group consisting of Pd¹⁺, Pd¹⁺/Ca, La and combinations thereof, and B is selected from the group consisting of Ti/Nb, Nb, Zr, Mn, Ta, V, Ti, W and combinations thereof.

2. The catalyst system of claim 1, wherein the washcoat further comprises at least one oxygen storage material.

3. The catalyst system of claim 1, wherein A is La.

4. The catalyst system of claim 1, wherein B comprises at least one stable (+5) cation.

5. The catalyst system of claim 1, wherein the at least one perovskite structured compound has the formula Pd¹⁺_0.5Ca²⁺_0.5Ti⁴⁺_0.50Nb⁵⁺_0.5O₃.

6. The catalyst system of claim 1, wherein the at least one perovskite structured compound has the formula Pd¹⁺_uCa²⁺_vD⁴⁺_wE⁵⁺_xO_y, wherein u+v=1, w+x=1, y>

3, and each of D and E are elements having a stable formal charge of (IV) and (V).

7. The catalyst system of claim 6, wherein u*1+v*2+w*4+x*5=6 when y=3.

8. The catalyst system of claim 6, wherein y>

2.7.

9. The catalyst system of claim 2, wherein the oxygen storage material may be about 0% to about 80% by weight of the washcoat.

10. The catalyst system of claim 1, wherein the at least one perovskite structured compound comprises about 1 g/ft³ to about 100 g/ft³ of Pd.

11. The catalyst system of claim 1, wherein the substrate comprises a honeycomb structure.

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

13. The catalyst system of claim 12, wherein the at least one ceramic portion is selected from the group consisting of cordierite, mullite, SiC, SiN, and combinations thereof.

14. The catalyst system of claim 1, wherein the substrate is shock resistant.

15. The catalyst system of claim 1, wherein the substrate is thermally resistant.

16. The catalyst system of claim 1, wherein at least a portion of the substrate comprises three-dimensional support for the washcoat.

17. A catalyst system, comprising:

a substrate; and

a washcoat suitable for deposition on the substrate, comprising at least one oxide solid selected from the group consisting of at least one carrier metal oxide, and at least one catalyst; and

wherein the at least one catalyst comprises at least one delafossite structured compound having the formula ABO₂ wherein A is Pd¹⁺ and B is selected from the group consisting of Sc, Cr, Mn, Fe, Co, Ga, A and combinations thereof.

18. The catalyst system of claim 17, wherein B comprises at least one stable (+3) cation.

19. The catalytic system of claim 17, further comprising a first impregnation layer wherein the first impregnation layer is heated to about 400°

C. to about 700°

C.

20. The catalytic system of claim 17, further comprising a second impregnation layer wherein the second impregnation layer is heated to about 400°

C. to about 700°

C.

21. The catalytic system of claim 17, further comprising an overcoat.