| 摘要 |
PURPOSE:To provide a titled catalyst which prevents poisoning of catalytically active noble metals with lead and can maintain high purifying performance for a long period of time by the constitution wherein the surface of a carrier layer for catalytically active noble metals is coated with an oxide layer forming a perovskite type compd. by capturing lead. CONSTITUTION:An active layer 4 consisting of active alumina contg. noble metals such as Pt, Rh, Pd or the like as a catalytically active component is provided on the surface of a ceramic base material 3 such as cordierite constituting a monolithic catalyst 1 of a honeycomb shape provided with many through-holes 2 and further a coating layer 5 consisting of oxide such as TiO2, Sc2O3, V2O5, BeO, MoO3 or the like forming a perovskite type compd. such as PbTiO3 or the like by capturing the Pb in waste gas of leaded gasoline is formed on the surface thereof. Said layer 5 protects the noble metals by capturing Pb, and since the formed perovskite type compd. has the co-catalytic effect, the catalytic activity is maintained at the much higher performance. |
