Hydrothermally stable, low-temperature NO
A catalyst composition includes a heterobimetallic zeolite characterized by a chabazite structure loaded with copper ions and at least one trivalent metal ion other than Al 3+ . The catalyst composition decreases NO x emissions in diesel exhaust and is suitable for operation in a catalytic converter.
1. A catalyst composition comprising a heterobimetallic zeolite characterized by a chabazite structure loaded with copper ions and iron(III) ions, wherein said copper ions are present in said catalyst in a loading amount of above 1 wt % and said iron(III) ions are present in said catalyst in a loading amount of less than 1 wt %, and said copper and iron loading amounts are effective to achieve a NO x conversion at 150° C. of at least 50% in the presence of an ammonia reductant.
2. A catalyst in accordance with claim 1 , wherein said iron(III) ions are in combination with at least one other trivalent metal ion.
3. A catalyst in accordance with claim 2 , wherein said at least one other trivalent metal ion is a trivalent transition metal ion.
4. A catalyst in accordance with claim 2 , wherein said at least one other trivalent metal ion is a trivalent lanthanide metal ion.
5. A catalyst in accordance with claim 2 , wherein said at least one other trivalent metal ion is a trivalent main group metal ion.
6. A catalyst in accordance with claim 1 , wherein said zeolite comprises CuFe-SSZ-13.
7. A catalytic converter comprising a catalyst loaded onto a refractory substrate, said catalyst comprising a heterobimetallic zeolite characterized by a chabazite structure loaded with copper ions and iron(III) ions, wherein said copper ions are present in said catalyst in a loading amount of above 1 wt % and said iron(III) ions are present in said catalyst in a loading amount of less than 1 wt %, and said copper and iron loading amounts are effective to achieve a NO x conversion at 150° C. of at least 50% in the presence of an ammonia reductant.
8. A catalytic converter in accordance with claim 7 , wherein said iron(III) ions are in combination with at least one other trivalent metal ion.
9. A catalytic converter in accordance with claim 8 , wherein said at least one other trivalent metal ion is a trivalent transition metal ion.
10. A catalytic converter in accordance with claim 8 , wherein said at least one other trivalent metal ion is a trivalent lanthanide metal ion.
11. A catalytic converter in accordance with claim 8 , wherein said at least one other trivalent metal ion is a trivalent main group metal ion.
12. A catalytic converter in accordance with claim 7 , wherein said zeolite comprises CuFe-SSZ-13.
13. A catalytic converter in accordance with claim 7 , wherein said refractory substrate is characterized by a structure selected from the group consisting of a rod structure, a honeycomb structure, and a pinwheel structure.
14. The catalyst of claim 1 , wherein said copper ions are present in said catalyst in a loading amount of at least 1.5 wt % and said iron(III) ions are present in said catalyst in a loading amount of less than 1 wt %.
15. The catalyst of claim 1 , wherein said copper ions are present in said catalyst in a loading amount of at least 2 wt % and said iron(III) ions are present in said catalyst in a loading amount of less than 1 wt %.