Exhaust gas purification catalyst device

Abstract

An exhaust gas purification catalyst device includes a substrate and one or more catalyst coating layers on the substrate, wherein the one or more catalyst coating layers include copper ion-exchanged zeolite and alkali-containing zeolite containing one or more metals selected from among alkali metals and alkaline earth metals, the exhaust gas purification catalyst device satisfying either of the following conditions (A) and (B): (A) both the copper ion-exchanged zeolite and the alkali-containing zeolite are contained in one of the catalyst coating layers, and (B) the catalyst coating layer includes a first catalyst coating layer containing the copper ion-exchanged zeolite and a second catalyst coating layer containing the alkali-containing zeolite, with the first catalyst coating layer and second catalyst coating layer being layered together in direct contact.

Dependencies are inferred from the claim text.