Pellet-type oxidation catalyst
AssigneeGeneral Motors Corporation
InventorsLouis Hegedus, Jack C. Summers
Life of this patent
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Abstract
This invention relates to oxidation catalysts wherein the catalytically active metallic material has an impregnation depth of at least 90 microns up to about 250 microns on the porous support which has a surface area of at least 100 m.sup.2 /g. up to about 250 m.sup.2 /g. and a pore structure characterized by a macropore volume of at least 0.020 cm.sup.3 /g. up to about 0.200 cm.sup.3 /g. and a macropore radius greater than about 10,000 A.
Claims5
A noble metal pellet-type oxidation catalyst comprising a porous alumina support member having a surface area of at least 100 m.sup.2 /g. up to about 250 l m.sup.2 /g. and a pore structure characterized by a macropore volume of at least 0.020 cm.sup.3 /g. up to about 0.200 cm.sup.3 /g. and a macropore radius greater than about 10,000 A, and a catalyst material selected from the group consisting of platinum and platinum/palladium deposited on said support to a depth of at least 90 microns up to about 250 microns, said pore structure serving to increase the diffusivity of the reactants into the interior of the catalyst, the surface area serving to compensate for the otherwise accelerated rate of poisoning caused by the increase in diffusivity, and the depth of deposit being such that the catalyst poisons do not break through the zone of deposit prior to the desired lifetime of the catalyst.
Dependencies are inferred from the claim text.