Engine exhaust catalysts comprising a substrate and a coating which is formed on the substrate and includes platinum, palladium and gold nanoparticles are provided to treat exhaust effectively gases containing CO and HC, and methods for producing the engine exhaust catalysts are provided. An engine exhaust catalyst comprises a substrate(210) and a coating(220) which is formed on the substrate and includes platinum, palladium and gold nanoparticles. The coating comprises a supported platinum-based catalyst containing the platinum nanoparticles and a supported palladium-gold catalyst containing the palladium and gold nanoparticles. The supported platinum-based catalyst comprises platinum and at least one metal. The supported platinum-based catalyst comprises platinum and palladium. The platinum-based catalyst comprises platinum and a promoter. The promoter comprises bismuth. The supported palladium-gold catalyst has a palladium to gold weight ratio ranging from about 0.5:1 to about 1:0.5. The second supported catalyst has a palladium to gold weight ratio ranging from about 0.5:1 to about 1:0.5. The second supported catalyst has a palladium to gold weight ratio of about 0.84:1.0. The coating further comprises bismuth.