| 摘要 |
PURPOSE:To provide a catalyst composed of Co3O4-containing zeolite having a particle diameter of 5000Angstrom or less and having high exhaust gas purifying activity even when the temp. of exhaust gas is low. CONSTITUTION:Zeolite containing Co3O4 having a particle diameter of 5000Angstrom or less as a catalytically active seed. The objective zeolite catalyst is produced, for example, by a method wherein zeolite and cobalt acetate are added to one or more kinds of monohydric alcohols such as ethyl alcohol, n-propyl alcohol or n-butyl alcohol and the resulting mixture is heated for several hr at 30-95 deg.C under stirring and subsequently washed with monohydric alcohol to be dried to obtain cobalt acetate hydroxide-containing zeolite which is, in turn, baked while gas with oxygen concn. of 0-below 22vol.% is passed through said zeolite at SV of 4000hr<-1> to obtain Co3O4-containing zeolite having a particle diameter of 5000Angstrom or less. This zeolite catalyst shows high purifying activity even when the temp. of exhaust gas is low. |
