EXHAUST GAS PURIFICATION CATALYST AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To enhance the sulfur poisoning resistance of an NOx absorbing component such as Ba which absorbs NOx in a lean atmosphere and to enhance the NOx removing performance. SOLUTION: A 1st layer (inner catalyst layer) 2 and a 2nd layer (outer catalyst layer) 3 are disposed on a carrier 1. The 1st layer 2 has a 1st noblemetal component such as Pt, an NOx absorbing component such as Ba and a 1st base material which carries these (e.g. an alumina-CeO2 mixture). The 2nd layer 3 has a 2nd noble metal component such as Pt or Rh, a K or Na component and a 2nd base material which carries these (e.g. a zeolite).