Catalyst for purifying exhaust gases and process for producing the same

A process for purifying carbon monoxide, hydrocarbons and nitrogen oxides in exhaust gases in oxygen-rich atmosphere, thereby purifying the exhaust gases, the process comprising:

• bringing exhaust gases in oxygen-rich atmosphere, whose oxygen concentration is more than required for oxidizing the components to be oxidized therein, into contact with a catalyst:
• the catalyst comprising:
• a catalyst substrate;
• a first porous support layer consisting essentially of a first porous support supporting palladium, at least one kind of NOx-occluding material selected from the group consisting of alkali metals, alkaline earth metals and rare earth elements, and at least one component having oxygen-occluding ability, wherein said first porous support layer is formed on a surface of said catalyst substrate;
• and
• a second porous support layer comprising a second porous support supporting at least platinum, wherein said second porous support layer is formed on a surface of said first porous support layer, and wherein said second porous support layer supports no components having oxygen-occluding ability.