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AssigneeHitachi, Ltd.
InventorsTetsuro Haga, Hiroshi Kawagoshi, Hisao Yamashita
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The present invention provides a poisoning-resistant catalyst for combustion of CO and inflammable gases which comprises an inorganic carrier, a noble metal active ingredient supported on said inorganic carrier, and silica supported on said noble metal active ingredient, said noble metal active ingredient comprising at least one member selected from the group consisting of Pt, Rh and Pd, the surface of said catalyst being richer in silica and the inner part of said catalyst becoming richer in said noble metal active ingredient the deeper from the surface said inner part becomes; and a catalytic combustion apparatus for burning inflammable gases in a starting gas by the use of said catalyst. Said catalyst has a high resistance to poisoning and has a high level of activity at a low temperature of 200.degree. C. or lower.
A poisoning-resistant catalyst for combustion of CO and inflammable gases in air containing a poisonous component for the catalyst which comprises an inorganic carrier, a noble metal active ingredient supported on said inorganic carrier, and silica supported on said noble metal active ingredient, said noble metal active ingredient comprising at least one member selected from the group consisting of Pt, Rh and Pd, an outer part of the surface of said catalyst being richer in silica and an inner part of said catalyst becoming richer in said noble metal active ingredient the deeper from the outer part of the surface said inner part becomes;
A poisoning-resistant catalyst for combustion of CO and inflammable gases in air containing a poisonous component for the catalyst which is produced by supporting at least one of metal salts of Pt, Rh and Pd on at least the surface layer of an inorganic carrier, carrying out primary firing at 700.degree.-800.degree. C., supporting colloidal silica on a part of the surface of the fired product, and then carrying out secondary firing at 400.degree.-600.degree. C.
Dependencies are inferred from the claim text.