초록 ▼

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 la

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.

대표청구항 ▼

What is claimed is: 1. 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 le

What is claimed is: 1. 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. 2. The exhaust gas cleaning catalyst according to claim 1, wherein the lower layer is formed of at least one metal oxide selected from the group consisting of zirconia, ceria, titania, silica, magnesia, alumina, ceria-zirconia composite oxide, and composite oxide thereof. 3. The exhaust gas cleaning catalyst according to claim 2, wherein said metal oxide constituting said lower layer is ceria-zirconia composite oxide. 4. The exhaust gas cleaning catalyst according to claim 1, wherein an average pore diameter in said lower layer is 2 μm. 5. The exhaust gas cleaning catalyst according to claim 1, wherein a thickness of said lower layer is 60 μm. 6. The exhaust gas cleaning catalyst according to claim 1, wherein said metal oxide constituting said upper layer is zirconia added with 1 to 10 wt % of yttria. 7. The exhaust gas cleaning catalyst according to claim 1, wherein a porosity of said upper layer is 20%. 8. The exhaust gas cleaning catalyst according to claim 1, wherein an average pore diameter in said upper layer is 1 μm. 9. The exhaust gas cleaning catalyst according to claim 1, further comprising one or more intermediate layers between said lower layer and upper layer. 10. The exhaust gas cleaning catalyst according to claim 9, wherein said intermediate layer is formed of at least one metal oxide selected from the group consisting of silica, alumina, zirconia, and ceria.