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US 7,547,656 B2Granted
Exhaust gas cleaning catalyst
AssigneeToyota Jidosha Kabushiki Kaisha
InventorMasahide Miura
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Abstract
An exhaust gas cleaning catalyst comprising: a carrier substrate; a catalyst carrying layer formed on the carrier substrate; and a noble metal catalyst carried by the catalyst carrying layer; wherein said catalyst carrying layer comprises at least two layers, and of the at least two layers, lower layer on the side of the carrier substrate is a metal oxide layer with porosity of 40˜75% and upper layer on the side of the top surface is a metal oxide layer having thermal conductivity of 5 W/mK or less.
Claims10
An exhaust gas cleaning catalyst comprising:
- a carrier substrate;
- a catalyst carrying layer formed on the carrier substrate;
- and
- a noble metal catalyst carried by the catalyst carrying layer;
- wherein said catalyst carrying layer comprises at least two layers, and of the at least two layers, (1) a lower layer on the side of the carrier substrate is a metal oxide layer with porosity of 40 to 75%;
- and (2) an upper layer on the side of the top surface is a metal oxide layer having thermal conductivity of 5 W/mK or less, and
- said metal oxide constituting said upper layer is zirconia or zirconia added with 1 to 10 wt % of yttria, and the upper layer having a thickness of 20 to 50 μm.
4 more elements
Dependencies are inferred from the claim text.