Process for Elimination of Hexavalent Chromium Compounds on Metallic Substrates within Zero-PGM Catalyst Systems

• US 20150148220A1
• Filed: 01/28/2015
• Published: 05/28/2015
• Est. Priority Date: 07/12/2013
• Status: Abandoned Application

• Current Assignee: Clean Diesel Technologies, Inc.
• Original Assignee: CDTI
• Inventors: Nazarpoor, Zahra
• Application Number:
  US14/607,486
• Publication Number:
  US 20150148220A1
• Time in Patent Office: Days
• US Class Current: 502/304
• CPC Class Codes: B01D 2251/202 Hydrogen
• CPC Class Codes: B01D 2251/204 Carbon monoxide
• CPC Class Codes: B01D 2251/2062 Ammonia
• CPC Class Codes: B01D 2255/104 Silver
• 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 2255/2066 Praseodymium
• CPC Class Codes: B01D 2255/2068 Neodymium
• CPC Class Codes: B01D 2255/20715 Zirconium
• CPC Class Codes: B01D 2255/2073 Manganese
• CPC Class Codes: B01D 2255/20738 Iron
• CPC Class Codes: B01D 2255/20746 Cobalt
• CPC Class Codes: B01D 2255/20753 Nickel
• CPC Class Codes: B01D 2255/20761 Copper
• CPC Class Codes: B01D 2255/20769 Molybdenum
• CPC Class Codes: B01D 2255/20776 Tungsten
• CPC Class Codes: B01D 2255/20784 Chromium
• CPC Class Codes: B01D 2255/20792 Zinc
• CPC Class Codes: B01D 2255/908 O2-storage component incorporated in the catalyst
• CPC Class Codes: B01D 53/46 : Removing components of defined structure
• CPC Class Codes: B01D 53/58 : Ammonia
• CPC Class Codes: B01D 53/62 : Carbon oxides
• CPC Class Codes: B01D 53/94 : by catalytic processes
• CPC Class Codes: B01J 23/10 : of rare earths
• CPC Class Codes: B01J 23/26 : Chromium
• CPC Class Codes: B01J 23/50 : Silver
• CPC Class Codes: B01J 23/66 : Silver or gold
• CPC Class Codes: B01J 23/72 : Copper
• CPC Class Codes: B01J 23/745 : Iron
• CPC Class Codes: B01J 23/83 : with rare earths or actinides
• CPC Class Codes: B01J 23/894 : with rare earths or actinides
• CPC Class Codes: B01J 35/56 : Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B01J 37/0036 : Grinding
• CPC Class Codes: B01J 37/0219 : the coating containing organic compounds
• CPC Class Codes: B01J 37/0225 : of metal substrates
• CPC Class Codes: B01J 37/0234 : Impregnation and coating simultaneously
• CPC Class Codes: B01J 37/0244 : Coatings comprising several layers
• CPC Class Codes: B01J 37/03 : Precipitation; Co-precipitation
• CPC Class Codes: B01J 37/16 : Reducing
• CPC Class Codes: B01J 37/18 : with gases containing free hydrogen
• CPC Class Codes: Y10S 502/50 : Stabilized
• CPC Class Codes: Y10S 502/514 : Process applicable either to preparing or to regenerating or to rehabilitating catalyst or sorbent
• CPC Class Codes: Y10S 502/52 : Suppressed side reactions
• CPC Class Codes: Y10S 502/521 : Metal contaminant passivation
• CPC Class Codes: Y10S 502/52712 : Plural layers on a support, each layer having a distinct function

Abstract

Process for manufacturing ZPGM catalysts systems that may allow the prevention of formation or the conversion of corrosion causing compounds, such as hexavalent chromium compounds, within ZPGM catalyst systems is disclosed. In one embodiment, disclosed ZPGM catalysts systems, may include metallic substrate, which may include alloys of iron and chromium, a washcoat and an overcoat. Disclosed manufacturing process may include a thermal decomposition of hexavalent chromium compounds which may allow the decomposition of such compounds into trivalent chromium compounds, and may also produce metallic catalyst, such as silver. Such conversion may prevent corrosion formation, such as red color corrosion within ZPGM catalyst system. An embodiment of the disclosed process may include a reducing agent, which may be present in exhaust conditions, which may convert hexavalent chromium compounds into trivalent chromium compounds as well as produce metallic catalyst, such as silver. Employing the disclosed manufacturing process may allow the production of ZPGM catalyst systems that may exhibit high activity and enhanced performance.

Claims

1. A method for reducing corrosion of a catalytic system, comprising:

providing a catalyst system, comprising;

a substrate; and

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

wherein the washcoat is aged; and

providing an exhaust stream having one selected from the group consisting of hydrogen, carbon monoxide, ammonia and combinations thereof.

2. The method according to claim 1, wherein aging is by heating to about 1100°

C.

3. The method according to claim 2, wherein the heating may continue for about 3 hours to about 6 hours.

4. The method according to claim 2, wherein the heating occurs in the presence of one selected from the group consisting of hydrogen, carbon monoxide, ammonia, and combinations thereof.

5. The method according to claim 1, wherein at least one hexavalent chromium compound is reduced.

6. The method according to claim 1, wherein aging is by heating to about 900°

C.

7. The method according to claim 6, wherein the heating may continue for about 3 hours to about 6 hours.

8. The method according to claim 6, wherein the heating occurs in the presence of one selected from the group consisting of hydrogen, carbon monoxide, ammonia, and combinations thereof.

9. The method according to claim 1, wherein the washcoat is at least partially prepared by co-milling.

10. The method according to claim 1, wherein the washcoat is heated to about 550°

C. for about 4 hours.

11. The method according to claim 1, wherein the substrate about 100 cells per square inch.

12. The method according to claim 1, wherein the substrate comprises metal.

13. The method according to claim 1, wherein at least one first catalyst is substantially free of platinum group metals.

14. The method according to claim 1, wherein at least one first catalyst comprises at least one selected from the group consisting of copper, cerium, silver, and combinations thereof.

15. The method according to claim 1, wherein the substrate comprises one selected from the group consisting of iron, chromium, and combinations thereof.