| 摘要 |
1462469 Exhaust gas treatment HOECHST AG 29 April 1974 [9 May 1973 14 March 1974] 18568/74 Heading C1A Carbon monoxide and hydrocarbons contained in the exhaust gas from an internal combustion engine are oxidized by catalytic reaction with an oxygen-containing gas to form carbon dioxide and water, the oxidation being performed at a temperature in the range 150 to 800‹ C. in contact with a carrier-supported catalyst whose activity is substantially independent of the concentration of oxygen in the gas mixture, the carriersupported catalyst being prepared by calcining aluminium oxide which is substantially free from alkali metal ions and silicate ions at a temperature in the range 1000 to 1200‹ C., impregnating it with one or more salts of copper manganese and nickel and heating to form copper, manganese and nickel aluminates, in a weight ratio of (2-4) : (1-2) : (0À1-1), the aluminates comprising 10 to 45 wt. per cent of the total weight of the carrier-supported catalyst. The catalyst may contain as an additional component 0À5 to 10 wt. per cent of cerium oxide, and this preferred catalyst may be prepared by impregnating the catalyst as prepared above with an aqueous solution of a decomposable cerium salt, drying it at a temperature in the range 130 to 150‹ C., heating first at a temperature in the range 200 to 300‹ C. and subsequently at a temperature in the range 450 to 550‹ C. to decompose the cerium salt, and then calcining at a temperature in the range 700 to 800‹ C. |
