CATALYST FOR EXHAUST PURIFICATION

摘要

PURPOSE:To obtain a highly durable catalyst for exhaust purification capable of maintaining an early-stage purification capability as it is by arranging the first layer of oxidation catalyst component on a carrier substrate and allowing the second layer consisting of cobalt and zeolite to be carried on the first layer. CONSTITUTION:The first layer 2 of activated alumina 20 on which an oxidation catalyst component such as Pt or Pd 21 is carried is formed on a carrier substrate 1 such as a monolithic carrier substrate or a pellet carrier substrate. Next, the second layer 3 consisting of zeolite 30 and cobalt 31 is formed as a carrier layer on the first layer 2. The catalyst thus obtained is capable of purifying NOx efficiently in an lean and burn atmosphere and also purifying HC and CO. In addition, the catalyst maintains an early-stage purification capability.