Exhaust gas purifying catalyst
AssigneeToyota Jidosha Kabushiki Kaisha
InventorMasahiko Ogai
Life of this patent
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Abstract
In an exhaust gas purifying catalyst, a catalyst supporting layer is formed on a surface of a cell wall of a honeycomb base member, and a catalytic noble metal and a NOx adsorbing material are loaded on the catalyst supporting layer. The portion of the catalyst supporting layer present within a depth of 100 .mu.m constitutes at least 80% by volume relative to a total volume of the catalyst supporting layer. The catalyst maintains a high probability of contact of emissions with the NOx adsorber and the catalytic noble metal, and allows easy decomposition of the sulfuric acid salt produced by sulfur poising of the NOx adsorber, thereby ensuring reliable recovery of the NOx purifying performance.
Claims20
An exhaust gas purifying catalyst comprising:
- a base member having a honeycomb structure, cells of said base member having a sectional shape of a regular hexagon;
- a catalyst supporting layer formed on a surface of a cell wall of said base member, said catalyst supporting layer having an outer surface that is in direct physical contact with exhaust gases to be purified;
- a catalytic noble metal loaded on said catalyst supporting layer;
- and
- a NOx adsorbing material loaded on said catalyst supporting layer,
- wherein said catalyst supporting layer is present in an amount of more than 100 g per liter of said base member and at least 80% by volume of said catalyst supporting layer relative to a total volume of said catalyst supporting layer is present within a depth of 100 .mu.m from said outer surface.
An exhaust gas purifying catalyst comprising:
- a base member having a honeycomb structure;
- a catalyst supporting layer formed on a surface of a cell wall of said base member, said catalyst supporting layer having an outer surface that is in direct physical contact with exhaust gases to be purified;
- a catalytic noble metal loaded on said catalyst supporting layer;
- and
- a NOx adsorbing material loaded on said catalyst supporting layer,
- wherein said catalyst supporting layer is present in an amount of more than 100 g per liter of said base member and at least 80% by volume of said catalyst supporting layer relative to a total volume of said catalyst supporting layer is present within a depth of 100 .mu.m from said outer surface.
Dependencies are inferred from the claim text.