Copper CHA Zeolite Catalysts

摘要

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

主权项

1. A catalyst article comprising a honeycomb wall-flow filter substrate having an SCR catalyst composition coated on the wall flow filter comprising a CuCHA zeolite catalyst having a mole ratio of silica to alumina greater than about 15 and an atomic ratio of copper to aluminum exceeding about 0.25, the SCR catalyst favoring reduction of nitrogen oxides and an ammonia oxidation catalyst coated on the wall flow filter, the ammonia oxidation catalyst favoring the oxidation of ammonia and comprising a CuCHA zeolite catalyst having a mole ratio of silica to alumina greater than about 15 and an atomic ratio of copper to aluminum exceeding about 0.25.