EXHAUST GAS PURIFICATION CATALYST APPARATUS USING SELECTIVE REDUCTION CATALYST, EXHAUST GAS PURIFICATION METHOD, AND DIESEL AUTOMOBILE MOUNTED WITH EXHAUST GAS PURIFICATION CATALYST APPARATUS

摘要

An exhaust gas purification catalyst apparatus is arranged with an oxidation catalyst (DOC) having a noble metal component for oxidizing a nitrogen oxide (NO) in exhaust gas discharged from a diesel engine, a reducing agent spraying means for supplying a reducing agent selected from an urea component or an ammonia component, and a selective reduction catalyst (SCR) for reducing the nitrogen oxide (NOx) by making contacted with the reducing agent, in this order from the upstream side of a flow passage of exhaust gas. The selective reduction catalyst (SCR) does not comprise the noble metal component and includes zeolite or a crystal metal aluminophosphate; and further, a trap means for collecting the noble metal component volatilized from the oxidation catalyst (DOC) is arranged between the oxidation catalyst (DOC) and the selective reduction catalyst (SCR), or the like.