catalyst article, exhaust gas treatment system, internal combustion engine exhaust flow treatment method and catalyst preparation method

摘要

catalyst articles comprising a substrate having catalyst coating thereon, wherein the catalyst coating comprises a catalyst layer having thickness, an inner surface close to the substrate and an outer surface distant from the substrate, wherein the catalyst layer comprises a metal component on noble support particles and the concentration of the noble metal component towards the other surface is higher than the concentration towards the inner surface, they are highly effective for treating exhaust gas flows from internal combustion engines. the articles are prepared by a method comprising providing the first blend comprising micron scale carrier particles and applying the first blend to a substrate to form a microparticle layer; providing a second mixture comprising nanoscale support particles and a noble metal component having initial ph; applying the second mixture to the microparticle layer; and substrate calcination.