Engelhard Corporation

Engelhard Minerals & Chemicals Corporation

John J Mooney

Carl D Keith

Joseph Charles Dettling

Charles E Thompson

William A Mannion

Robert E Kenson

Daniel L Bair

Samuel J Tauster

Michael P Galligan

Saul G Hindin

Robert M Skomoroski

Jack J Early

H Shinn Hwang

Ronald J Brown

The present invention is directed to a catalyzed metallic substrate, such as a metal plate. There is a catalyst layer supported on the substrate surface. The article is useful as part of exhaust systems which can be used with small engines for applications such as motorcycles, lawn mowers, chain saws, weed trimmers and the like. The present invention includes methods to prepare the catalyzed metal substrate and methods of use of the catalyzed substrate.

Catalytic metal plate

H.sub.2 S formation by three-way catalyst is suppressed by incorporating nickel, manganese or iron oxides into an undercoat layer disposed on a substrate, such as a monolith substrate. A topcoat overlying the undercoat is comprised of a three-way catalyst material which includes one or more of platinum, rhodium and palladium as catalytic metals.

Hydrogen sulfide-suppressing catalyst system

This invention provides polyfunctional catalysts comprising a composite of platinum and one or more of rhodium, ruthenium and iridium, a substantially larger quantity of one or more base metal oxides in which the metal is selected from the group consisting of metals having an atomic number from 25 to 28 and rhenium, and an alumina support, which composite is made and then deposited on a suitable carrier. In a preferred embodiment, the catalysts contain 1-20 weight percent of said base metal oxide, typically nickel oxide; 0.05-0.5 weight percent platinum; and 0.002-0.3 weight percent rhodium, and an alumina support deposited on a monolith or other carrier. The improved catalysts are especially applicable for purifying exhaust gases from combustion processes, and in particular those from internal combustion engines. These polyfunctional catalysts have in a single formulation, the ability to accomplish four objectives--to oxidize carbon monoxide and unburned hydrocarbons while reducing nitrogen oxides, thereby converting those contaminants found in the exhaust of internal combustion engines into carbon dioxide, water and elemental nitrogen, but without producing significant amounts of hydrogen sulfide, sulfur trioxide or sulfuric acid. Such chemical conversions take place over the catalyst when the ratio of air to fuel supplied to the catalyst is controlled to nearly stoichiometric conditions, thereby maintaining the exhaust feed gases within a narrow compositional range, sometimes called a 'window', in which the catalyst can substantially convert the contaminants.

Polyfunctional catalysts and method of use

A catalytic promoting material is supported on a monolithic support member, of the type generally referred to as a 'honeycomb' support, having longitudinal fluid flow channels extending through it. The catalytically promoting material is dispersed as a coating on the walls of the fluid flow channels which are nominally polygonal, preferably nominally square, in cross section profile so that the walls forming the flow channels can be made as thin as possible consistent with an acceptable thermal and mechanical strength. However, the juncture of the channel walls forming the flow channels are filleted to provide a concave profile, preferably one having an arcuate shape in cross section, so that the corners are 'filleted' or 'rounded', to subtend an appreciable segment of the nominal width of the channel wall. This prevents or at least reduces the accumulation of excess catalytic material which occurs in the sharp angular corners of prior art structures.

Monolithic catalyst member and support therefor

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.

Catalyst for reducing pollutants in waste gas streams and process for

An air-to-fuel ratio control mechanism in an internal combustion engine operates in partial response to the output of a control circuit, which circuit in turn is responsive to the output of an oxygen sensor mounted in the exhaust of the engine. The control circuit biases the control mechanism toward a predetermined desired air-to-fuel ratio, normally at or near stoichiometric. When the sensor output deviates above a first predetermined value or below a second predetermined value for longer than a predetermined time period, a comparator circuit provides a disabling signal which disconnects the control circuit from the air-to-fuel ratio control mechanism. At the same time, the disabling signal connects a predetermined signal to the air-to-fuel ratio control mechanism. This predetermined signal simulates a nominal control circuit output to maintain the air-to-fuel ratio close to stoichiometric or some other preferred setting such as a air/fuel ratio which is lean. An indicator is turned on by the disabling signal to alert the operator to possible malfunction.

Oxygen sensor control system

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 on a relatively catalytically-inactive carrier, especially a monolithic carrier which may be of the honeycomb type. An aqueous solution of an alumina precursor 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.

Catalyst and process of its preparation

This invention provides polyfunctional catalysts comprising a composite of platinum and one or more of rhodium, ruthenium and iridium, a substantially larger quantity of one or more base metal oxides in which the metal is selected from the group consisting of metals having an atomic number from 25 to 28 and rhenium, and an alumina support, which composite is made and then deposited on a suitable carrier. In a preferred embodiment, the catalysts contain 1-20 weight percent of said base metal oxide, typically nickel oxide; 0.05-0.5 weight percent platinum; and 0.002-0.3 weight percent rhodium, and an alumina support deposited on a monolith or other carrier. The improved catalysts are especially applicable for purifying exhaust gases from combustion processes, and in particular those from internal combustion engines. These polyfunctional catalysts have in a single formulation, the ability to accomplish four objectives - to oxidize carbon monoxide and unburned hydrocarbons while reducing nitrogen oxides, thereby converting those contaminants found in the exhaust of internal combustion engines into carbon dioxide, water and elemental nitrogen, but without producing significant amounts of hydrogen sulfide, sulfur trioxide or sulfuric acid. Such chemical conversions take place over the catalyst when the ratio of air to fuel supplied to the catalyst is controlled to nearly stoichiometric conditions, thereby maintaining the exhaust feed gases within a narrow compositional range, sometimes called a 'window,' in which the catalyst can substantially convert the contaminants.

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Wyckoff, NJ, United States of America

John J Mooney