| abstract |
Exhaust gas purification catalyst, the catalyst comprising: DOLLAR A a substrate DOLLAR A, a catalyst layer on the substrate, the catalyst layer comprising at least one catalyst metal and at least one alkali metal and / or alkaline earth metal as a NO¶x¶ absorbent, and DOLLAR A a barrier layer on the catalyst layer, the barrier layer comprising an inorganic oxide layer bearing at least one noble metal and at least one transition metal, and wherein the barrier layer acts to inhibit the diffusion of SO¶x¶ into the NO¶x¶ absorbent. |