| 摘要 |
PURPOSE:To provide such a catalyst for purification of exhaust gas from an engine that has excellent low temp. activity for HC and contains Pd as a catalyst component and that contamination of Pd with S can be suppressed. CONSTITUTION:A first catalyst layer consisting of Pd carried on Al2O3 is formed on the surface of a carrier, and a second catalyst layer consisting of Pd carried on CeO2 is formed on the first layer. This catalyst is produced by the following method. An aq. soln. of dinitrodiamine Pd is added to a slurry containing Al2O3 by vacuum sucking and stirred to prepare a slurry in which Pd particles 6 are widely dispersed inter primary particles 4 and inter secondary particles 5 of Al2O3. Then a carrier is immersed in this slurry, dried and calcined. Another slurry containing Pd carried on primary particles and secondary particles of CeO2 is prepared by the same method as above described, and the carrier is immersed in the slurry, dried and calcined. Therefore, since Pd is dispersed among inter the primary particles, SO2 is hardly adsorbed and contamination of Pd with S is suppressed. |
