| 摘要 |
PURPOSE:To obtain a catalyst which exhibits excellent power to stably reduce three components, i.e. CO, HC and NOx, over a wide range of air/fuel ratio at a high temp. above 800 deg.C, by supporting one or more of activated alumina, iron oxide, etc., one or more of platinum-group metals and Rh on a honeycomb carrier having a unitary structure. CONSTITUTION:A honeycomb carrier (esp. pref. a cordierite one) having a unitary structure is prepared. On the basis of 1l said carrier, 50-200g alumina, 5-30g ceria, 2-15g neodymia, 1-8g zirconia and one or more of 0-5g (in terms of Fe2O3) iron oxide and 0-10g (in terms of NiO) nickel oxide are supported. On the basis of 1l said carrier, 0.1-10g Pt and/or Pd and Rh are further supported in addition to said catalytic components. Hereon, the ratio of Rh to Pt and/or Pd is used in a range of 1:100-1:1. The obtd. catalyst can make HC, CO and NOx existent in exhaust gas substantially unoxious. It is a high-temp. durable monolithic catalyst for the purification of exhaust gas which is scarcely deteriorated even when being subjected to said high temp. |
