Catalyst for purifying exhaust gas
AssigneeCataler Corporation
InventorsKoichi Kasahara, Yasunori Sato, Kenichi Taki
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Abstract
A catalyst for purifying exhaust gases, which enables the HC-purification performance to be further improved by suitably arranging an HC-adsorbent. The catalyst includes a coating layer which is composed of alumina and zeolite, and carries a noble metal. The weight ratio of alumina and zeolite in the coating layer ranges from 5:1 to 1:1. Zeolite adsorbs HC when exhaust gases are in a low temperature region, and HC desorbed from zeolite is oxidized and purified with the noble metal.
Claims10
A catalyst for purifying exhaust gases, comprising:
- a substrate having heat resistance;
- a coating layer which is composed of a carrier containing alumina as a main component, and zeolite, and formed on a surface of said substrate;
- and
- a noble metal which is carried by said coating layer, the weight ratio of alumina and zeolite in said coating layer ranging from 5:1 to 1:1.
A catalyst for purifying exhaust gases, comprising:
- a substrate having heat resistance;
- an HC-adsorbent layer which is formed on a surface of said substrate;
- a lower catalyst layer which is composed of a porous carrier carrying Pd, and is formed on a surface of said HC-adsorbent layer;
- and
- an upper catalyst layer which is composed of a porous carrier carrying Pt and Rh, and is formed on a surface of said lower catalyst layer.
A catalyst as claimed in claim wherein said HC-adsorbent is zeolite.
Dependencies are inferred from the claim text.