초록 ▼

Macrosized catalysts suitable for promoting chemical reactions, especially to reduce pollutants in waste gas streams such as automobile exhaust, are described. The catalysts have one or more metal components, especially a platinum group metal component, as a catalytic promoter combined with a high s

Macrosized catalysts suitable for promoting chemical reactions, especially to reduce pollutants in waste gas streams such as automobile exhaust, are described. The catalysts have one or more metal components, especially a platinum group metal component, as a catalytic promoter combined with a high surface area, refractory oxide support. Alumina is added to the macrosize catalyst to provide protection against poisoning by extraneous materials such as lead, zinc, other metals, sulfur or phosphorus with which the catalysts may come in contact during use. These catalysts may have a relatively catalytically-inactive carrier, especially a monolithic carrier which may be of the honeycomb type.

대표청구항 ▼

In a process of preparing a macrosize catalytic composition suitable for use in the oxidation of carbonaceous materials, and/or the reduction of nitrogen oxides, the steps which comprise depositing an aqueous slurry of particles of a major amount of catalytically-active alumina or a hydrous alumina

In a process of preparing a macrosize catalytic composition suitable for use in the oxidation of carbonaceous materials, and/or the reduction of nitrogen oxides, the steps which comprise depositing an aqueous slurry of particles of a major amount of catalytically-active alumina or a hydrous alumina precursor thereof and a minor amount of one or more rare earth oxides, on the surface of a macrosize catalyst consisting essentially of a catalytically-effective amount of catalytically-active promoting metal component and high area, refractory oxide support, the promoting metal being susceptible to poisoning by extraneous materials and the amount of said deposit being sufficient to increase the resistance of the catalyst to poisoning by extraneous materials, and drying said composition subsequent to said deposition.