NOx SORPTION AND REDUCTION CATALYST AND METHOD FOR USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an NOx sorption and reduction catalyst which has a high NOx sorption capacity even after a high-temperature durability test (750 deg.C×5 hr), can sufficiently sorb NOx in a temperature range above 600 deg.C, and can exhibit a high NOx reduction rate and to provide a method for using the same. SOLUTION: This catalyst is prepared by infiltrating a noble metal and an NOx sorbent into a coat layer based on a support comprising a compound oxide having a magnesia/alumina spinel structure and a specific surface area of at least 50 m2/g and containing 8-20 wt.% alumina binder. The support is strongly basic and lowly reactive with the sorbent, so that the consumption of the sorbent by the reaction with the support can be reduced. Even when the sorbent undergoes a volume change after repeated NOx sorption and reduction, the alumina binder prevents the coat layer form being peeled.