CATALYST FOR PURIFYING EXHAUST GAS AND PREPARATION THEREOF

PURPOSE:To make it possible to sustain activity to both carbon monooxide and hydrocarbon to a max. degree, by a catalyst for purifying an exhaust gas obtained by combining a Pd and Pt containing part and a Pt containing part. CONSTITUTION:A shaped carrier (e.g., an alumina carrier) is impregnated with an aqueous solution of water solube compounds of Pd and Pt while a separate shaped carrier is impregnated with an aqueous solution of a water soluble Pt compound and, after drying, both impregnated carriers are reduced with a reducing agent (e.g., alkaline formalin) to precipitate a mixture of Pd-black and Pt-black and Pt-black on respective shaped carriers. The formed shaped carriers containing active components are mixed or combined in an appropriate amount or an appropriate number. That is, because a part containing Pd and Pt and a part only containing Pt are partitioned except the contact surfaces or the boundary surfaces thereof, activity characterized in the oxidation of carbon monooxide due to the part containing Pd and Pt and the oxidation of hydrocarbon due to the part containing only Pt can be developed to a max. degree for a long time.