Achieving EURO III and EURO IV With Ultra-Low Precious Metal Loadings

The automotive catalyst faces a unique set of challenges. It must simultaneously carry out oxidation and reduction reactions, all with a high degree of efficiency. It must cope with a gas composition that oscillates rapidly between oxidizing and reducing and is laden with poisons, such as sulfur and phosphorous. Equally harsh are the temperature demands. After being subjected to 1,000°C, the catalyst must “light off” at 250°C.

Despite these formidable demands, the automotive catalyst has proven itself over decades of operation during which time it has had a major impact on air quality. This success can be ascribed to a few key components of the catalyst: the Precious metals (Pt, Pd and Rh) and cerium oxide.

This paper describes the development of a new generation of three way catalysts that meet the latest European emission standards with a minimum of precious metal content