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THE DEVELOPMENT of a novel precious metal catalyst system supported on a metal substrate is outlined. The key nature of the metallic species is demonstrated. A high performance alloy, FECRALLOY STEEL®, is identified as a suitable material. Conversion of this alloy into a durable catalyst using a proprietary pre-treatment to render it compatible with existing catalysts and production procedures is discussed. The flexibility in processing with respect to key design features e.g. cell density, is emphasised. The influence of support variables such as volume, cell density etc., on the performance of an oxidation catalyst is reported together with comparable data for ceramic supported catalyst. It is shown that at zero hours, equivalent performance, at no power loss penalty relative to ceramics, can be secured by judicious choice of cell density/volume combinations. Such equivalence can be achieved with significantly lower volumes and significant scope exists for further optimisation.

Metal substrates have been available as catalyst supports for the past 10 years but their use has been limited to a few specialised applications, for example as light-off or starter catalysts for large cars. The emergence of Europe as an autocatalyst market with differing requirements has prompted a reassessment of the potential for metal supported catalysts. This paper will review much of the work conducted; in particular washcoat adhesion, hot-shake and high speed durability as well as reporting the results of a volume/cell density parametric study, comparing metal supported catalysts with ceramic supported catalysts on vehicles.