LAYERED EXHAUST GAS PURIFICATION CATALYST COMPRISING DIFFERENT NOBLE METALS

摘要

An exhaust gas purification catalyst includes a base material having a gas passage through which exhaust gas flows, a lower catalyst layer formed on a surface of the base material, and an upper catalyst layer that is formed on a surface of the lower catalyst layer. The upper catalyst layer supports Rh. The lower catalyst layer is formed by a Pd support layer that supports Pd and/or a Pt support layer that supports Pt. A length of the upper catalyst layer in a gas flow direction is less than a length of the lower catalyst layer in the gas flow direction.