Low phosphorus chabazites

摘要

A catalyst composition is provided having a CHA crystal structure; about 0.5 to about 5.0 mol % phosphorus; and SiO2 and Al2O3 in a mole ratio of about 5 to about 40. The catalyst composition is capable of NOx conversion at elevated temperatures. A catalytically active washcoat includes such catalyst compositions and one or more promoters or stabilizers, and may be applied to a monolith substrate to produce a catalytically active article. Methods of reducing NOx employing the catalyst compositions are also provided.

主权项

1. A composition comprising a crystalline structure, wherein at least a portion of the crystalline structure is a molecular sieve having a chabazite framework consisting of thirty-six T-atoms selected from the group consisting of silicon, aluminum, and phosphorus;
wherein said molecular sieve comprises about 0.05 to about 5.0 mole percent of framework phosphorus based on the total moles of framework silicon, aluminum, and phosphorus in said molecular sieve; and wherein said molecular sieve has a silica-to-alumina mole ratio of at least about 10.