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. The key role of cell density in this respect is identified and an optimum value in the region of 500 cells per square inch is indicated.Durability data is reported for various concepts and it is demonstrated that equivalence to ceramics can be achieved at extended operating periods over small volumes of metal substrates. The equivalence of two support types is established, one of which offers a significant reduction in the weight of Fecralloy®Steel used per unit volume and, therefore, in the material cost.