THERMALLY DURABLE, LOW H2S THREE WAY CATALYSTS

摘要

Improved platinum group three-way catalyst composition comprising (a) a high temperature catalyst support material, (b) a low temperature catalyst support material, (c) at least one platinum group metal, and (d) a metal additive effective for the suppression of hydrogen sulfide emissions, that is disposed in a separate layer either under or over a layer comprising the constituents (a), (b), and (c), or in the same layer as the constituents (a), (b), and (c). When the metal additive is disposed in the same layer as the constituents (a), (b), and (c), (d) the metal additive is disposed in a physical structure that is segregated from the remaining components in the layer.