초록 ▼

An exhaust gas purifying catalyst that provides the excellent low-temperature activity and also develops the good catalytic activity of rhodium to produce a good purifying performance economically. The exhaust gas purifying catalyst comprises an alumina on which rhodium and platinum are previously

An exhaust gas purifying catalyst that provides the excellent low-temperature activity and also develops the good catalytic activity of rhodium to produce a good purifying performance economically. The exhaust gas purifying catalyst comprises an alumina on which rhodium and platinum are previously supported; a zirconium complex oxide on which rhodium and platinum are previously supported; and a cerium complex oxide on which platinum is previously supported.

대표청구항 ▼

The invention claimed is: 1. An exhaust gas purifying catalyst comprising: an alumina on which rhodium and platinum are previously supported; a zirconium complex oxide on which rhodium and platinum are previously supported, and a cerium complex oxide on which platinum is previously supported. 2.

The invention claimed is: 1. An exhaust gas purifying catalyst comprising: an alumina on which rhodium and platinum are previously supported; a zirconium complex oxide on which rhodium and platinum are previously supported, and a cerium complex oxide on which platinum is previously supported. 2. The exhaust gas purifying catalyst according to claim 1, wherein the zirconium complex oxide comprises zirconium and cerium in a proportion of a zirconium content being more than a cerium content; and wherein the cerium complex oxide comprises cerium and zirconium in a proportion of a cerium content being more than a zirconium content. 3. The exhaust gas purifying catalyst according to claim 1 wherein the zirconium complex oxide is a heat-resisting oxide expressed by the following general formula (1): Zr1-(a+ b)CeaNbO2-c (1) (In the formula, N represents alkaline earth metal or rare earth metal, c represents oxygen vacancy, a represents a proportion of atom of 0.10-0.35, b represents a proportion of atom of 0-0.20, and 1-(a+ b) represents a proportion of atom of 0.45-0.90), and wherein the cerium complex oxide is a heat-resisting oxide expressed by the following general formula (2): Ce1-(x+ y)ZrxMyO2-z (2) (In the formula, M represents alkaline earth metal or rare earth metal, z represents oxygen vacancy, x represents a proportion of atom of 0.20-0.70, y represents a proportion of atom of 0-0.20, and 1-(x+ y) represents a proportion of atom of 0.10-0.80). 4. The exhaust gas purifying catalyst according to claim 1, which is presented in a form of an outermost layer of multi-coating layers formed on a catalyst carrier. 5. The exhaust gas purifying catalyst according to claim 4, wherein alumina on which palladium is supported is contained in at least one layer of the multi-coating layers, except the outermost layer. 6. The exhaust gas purifying catalyst according to claim 5, wherein rhodium is not contained in a layer containing alumina on which palladium is supported.