Achieving EURO-III and EURO-IV with Ultra-Low Precious Metal Loadings 2007-26-017
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 up with a gas composition that oscillates rapidly between oxidizing and reducing state and is laden with poisons, such as sulfur and phosphorous. Equally harsh are the temperature demands. After being subjected to temperature upto 1000 °C, the catalyst must “light off” at 250°C.
Despite these formidable demands, the automotive catalysts have been proven over decades of operation and have a major impact on improving 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.