Passive NOx adsorber

摘要

A passive NOx adsorber is disclosed. The passive NOx adsorber is effective to adsorb NOx at or below a low temperature and release the adsorbed NOx at temperatures above the low temperature. The passive NOx adsorber comprises a noble metal and a small pore molecular sieve. The small pore molecular sieve has a maximum ring size of eight tetrahedral atoms. The invention also includes an exhaust system comprising the passive NOx adsorber, and a method for treating exhaust gas from an internal combustion engine utilizing the passive NOx adsorber.