High silica chabazite for selective catalytic reduction, methods of making and using same
View Patent ↗There is disclosed a microporous crystalline material comprising a metal containing chabazite having a crystal size greater than 0.5 microns and a silica-to-alumina ratio (SAR) greater than 15, wherein the metal containing chabazite retains at least 80% of its initial surface area and micropore volume after exposure to temperatures of up to 900° C. in the presence of up to 10 volume percent water vapor for up to 1 hour. Methods of using the disclosed crystalline material, such as in the SCR of NO x in exhaust gas are also disclosed, as are methods of making such materials.
1. A zeolitic material comprising a copper containing chabazite having a crystal size greater than 0.5 microns and a silica-to-alumina ratio (SAR) greater than 15, wherein said copper containing chabazite retains at least 80% of its initial surface area and micropore volume after exposure to temperatures of up to 900° C. in the presence of up to 10 volume percent water vapor for up to 1 hour.
2. A zeolitic material of claim 1 , wherein said copper containing chabazite has a SAR ranging from 15-60.
3. A zeolitic material of claim 2 , wherein said SAR ranges from 20-60.
4. A zeolitic material of claim 1 , wherein said copper is introduced by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.
5. A zeolitic material of claim 1 , wherein said copper comprises at least 1.0 weight percent of the total weight of said material.
6. A zeolitic material of claim 5 , wherein said copper comprises an amount ranging from 1.0 to 4.0 weight percent of the total weight of said material.
7. A zeolitic material of claim 1 , wherein said initial surface area of said copper containing chabazite is at least 650 m 2 /g.
8. A zeolitic material of claim 1 , wherein said initial micropore volume of said copper containing chabazite is at least 0.25 cc/g.
9. A zeolitic material of claim 1 , wherein said crystal size of said copper containing chabazite ranges from 0.5 to 5.0 microns.
10. A method of selective catalytic reduction (SCR) of NOx in exhaust gas, said method comprising:
contacting exhaust gas with a zeolitic material comprising a copper containing chabazite having a crystal size greater than 0.5 microns and a silica-to-alumina ratio (SAR) greater than 15, wherein said copper containing chabazite retains at least 80% of its initial surface area and micropore volume after exposure to temperatures of up to 900° C. in the presence of up to 10 volume percent water vapor for up to 1 hour.
11. The method of claim 10 , wherein said contacting step is performed in the presence of ammonia or urea.
12. The method of claim 10 , wherein said chabazite has a SAR ranging from 15-60.
13. The method of claim 12 , wherein said SAR ranges from 20-60.
14. The method of claim 1 , wherein said copper is introduced by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.
15. The method of claim 1 , wherein said copper comprises at least 1.0 weight percent of the total weight of said material.
16. The method of claim 15 , wherein said copper comprises an amount ranging from 1.0 to 4.0 weight percent of the total weight of said material.
17. The method of claim 10 , wherein said initial surface area of said copper containing chabazite is at least 650 m 2 /g.
18. The method of claim 10 , wherein said initial micropore volume of said metal containing chabazite is at least 0.25 cc/g.
19. The method of claim 10 , wherein said crystal size of said copper containing chabazite ranges from 0.5 to 5.0 microns.
20. A method of selective catalytic reduction (SCR) of NO x in exhaust gas, said method comprising:
providing an article comprising a zeolitic material comprising a copper containing chabazite having a crystal size greater than 0.5 microns and a silica-to-alumina ratio (SAR) greater than 15; and
contacting said article with exhaust gas comprising NO x ,
wherein said copper containing chabazite retains at least 80% of its initial surface area and micropore volume after exposure to temperatures of up to 900° C. in the presence of up to 10 volume percent water vapor for up to 1 hour.
21. The method of claim 20 , wherein said contacting step is performed in the presence of ammonia or urea.
22. The method of claim 20 , wherein said chabazite has a SAR ranging from 15-60.
23. The method of claim 22 , wherein said SAR ranges from 20-60.
24. The method of claim 20 , wherein said copper is introduced by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.
25. The method of claim 20 , wherein said copper comprises at least 1.0 weight percent of the total weight of said material.
26. The method of claim 25 , wherein said copper comprises an amount ranging from 1.0 to 4.0 weight percent of the total weight of said material.
27. The method of claim 20 , wherein said initial surface area of said copper containing chabazite is at least 650 m 2 /g.
28. The method of claim 20 , wherein said initial micropore volume of said copper containing chabazite is at least 0.25 cc/g.
29. The method of claim 20 , wherein said crystal size of said copper containing chabazite ranges from 0.5 to 5.0 microns.
30. The method of claim 20 , wherein said article is in the form of a channeled or honeycombed-shaped body; a packed bed; microspheres; or structural pieces.
31. The method of claim 20 , wherein said packed bed comprises balls, pebbles, pellets, tablets, extrudates, other particles, or combinations thereof.
32. The method of claim 30 , where said structural pieces are in the form of plates or tubes.
33. The method of claim 30 , wherein the channeled or honeycombed-shaped body or structural piece is formed by extruding a mixture comprising the chabazite molecular sieve.
34. The method of claim 30 , wherein the channeled or honeycombed-shaped body or structural piece is formed by coating or depositing a mixture comprising the chabazite molecular sieve on a preformed substrate.