| 摘要 |
PURPOSE:To obtain a catalyst for purifying exhaust gas reducing CO and hydrocarbon and converting NO2 to NO, by simultaneously supporting palladium and zirconium oxide in a specific mixing ratio by a carrier by the use of a carrier solution having an org. acid added thereto. CONSTITUTION:An org. acid such as citric acid is added to an aqueous solution mixture of a palladium metal precursor such as dinitrodiamine palladium nitrate and a zirconium oxide precursor such as zirconium oxynitrate and a carrier such as a silica/alumina carrier is immersed in said solution mixture. The impregnated carrier is dried and subsequently baked to decompose the precursors to simultaneously support palladium and zirconium oxide. The mixing ratio of palladium and zirconium oxide is set to 1:2-1:50 on a wt. basis and the addition amount of the org. acid to zirconium oxide is set to 1:1-1:5 on a wt. basis. The obtained catalyst converts CO and hydrocarbon in the combustion exhaust gas within a usual oxygen excessive atmosphere to CO2 and H2O and converts NO2 strongest in toxicity in NOx to NO having lower toxicity. |
