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AssigneeAllied-Signal Inc.
InventorsMaureen L. Bricker, R. Joe Lawson
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This invention relates to a catalytic composite for treating an exhaust gas comprising a support which is a refractory inorganic oxide having dispersed thereon lanthanum, at least one other rare earth component and at least one noble metal component selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium. An essential feature of said catalytic composite is that the lanthanum be present as crystalline particles of lanthanum oxide which have an average crystallite size of less than about 25 Angstroms. The support may be selected from the group consisting of alumina, silica, titania, zirconia, aluminosilicates and mixtures thereof with alumina being preferred. This invention also relates to a method of manufacturing said catalytic composite. In particular, an important feature of said method of manufacturing is the dispersion of lanthanum oxide onto said refractory inorganic oxide support.
A catalytic composite for treating an exhaust gas comprising a support which is a refractory inorganic oxide selected from the group consisting of alumina, silica, titania, zirconia, alumino-silicates and mixtures thereof, having dispersed thereon lanthanum oxide, the lanthanum oxide being dispersed on said support by the method of commingling a solution of a lanthanum salt with a hydrosol of the metal precursor of said support, forming particles from said lanthanum containing hydrosol, calcining said particles to form a particulate support containing lanthanum oxide, having an average crystallite size of less than 25 Angstroms, at least one other rare earth oxide and at least one noble metal component selected from the group consisting of platinum, palladium, rhodium, ruthenium and iridium.
A method of manufacturing a catalytic composite comprising coating a metallic or ceramic solid honeycomb carrier with a support, which is a refractory inorganic oxide, having dispersed thereon lanthanum oxide and at least one other rare earth oxide, the lanthanum oxide being dispersed on said support by commingling a solution of a lanthanum salt with a hydrosol of the metal percursor of said support, forming particles from said lanthanum containing hydrosol, calcining said particles to form a particulate support containing lanthanum oxide, and grinding said calcined particles to yield a powder of said support containing lanthanum oxide having an average crystallite size of less than 25 Angstroms, calcining the resultant coated honeycomb carrier, dispersing at least one noble metal component selected from the group consisting of platinum, palladium, rhodium, ruthenium, and iridium onto said coated honeycomb carrier, calcining and recovering the resultant catalytic composite.
Dependencies are inferred from the claim text.