Copper containing levyne molecular sieve for selective reduction of NOx
Aspects of the present invention relates to a copper containing Levyne molecular sieve having a silica to alumina mole ratio less than 30 and a Cu:Al atomic ratio less than 0.45, wherein the Levyne molecular sieve retains at least 60% of its surface area after exposure to a temperature of from about 750° C. to about 950° C. in the present of up to 10 volume percent water vapor for a time ranging from about 1 to about 48 hours.
1. A copper-containing Levyne molecular sieve having a silica to alumina mole ratio of from about 15 to about 26 and a Cu:Al atomic ratio of from about 0.20 to about 0.45.
2. The copper-containing Levyne molecular sieve of claim 1 , wherein the silica to alumina mole ratio is less than 23.
3. The copper-containing Levyne molecular sieve of claim 1 , wherein the atomic ratio of copper to proton is less than 7.
4. The copper-containing Levyne molecular sieve of claim 1 , wherein moles Cu per 100 g zeolite (calculated as moles) are more than 0.01.
5. The copper-containing Levyne molecular sieve of claim 1 , wherein Cu content of the copper containing Levyne molecular sieve, calculated as CuO, is from about 2 to about 4 wt.-% based on the total weight of the calcined Levyne molecular sieve.
6. The copper-containing Levyne molecular sieve of claim 1 , wherein the Cu:Al atomic ratio is from about 0.2 to about 0.4.
7. The copper-containing Levyne molecular sieve of claim 1 , wherein the Levyne molecular sieve is a ZSM-45.
8. The copper-containing Levyne molecular sieve of claim 1 , wherein the Levyne molecular sieve is a Nu-3.
9. A catalyst containing the copper-containing Levyne molecular sieve of claim 1 disposed on a substrate.