A catalyst composition suitable for three-way conversion of internal combustion engine, eg, automobile gasoline engine, exhaust gases includes a catalytic material disposed in two discrete coats on a carrier The first coat includes a stabilized alumina support on which a first platinum catalytic component is dispersed and bulk ceria, and may also include bulk iron oxide, a metal oxide (such as bulk nickel oxide) which is effective for the suppression of hydrogen sulfide emissions, and one or both of baria and zirconia dispersed throughout the first coat as a thermal stabilizer The second coat, which may comprise a top coat overlying the first coat, contains a co-formed (eg, co-precipitated) rare earth oxide-zirconia support on which a first rhodium catalytic component is dispersed, and a second activated alumina support having a second platinum catalytic component dispersed thereon The second coat may also include a second rhodium catalytic component, and optionally, a third platinum catalytic component, dispersed as an activated alumina support The present invention also provides a method for treating engine exhaust gases by contacting the gases under conversion conditions with the catalyst composition

Catalyst composition containing segregated platinum and rhodium components

An exhaust gas-purifying catalyst includes a substrate, and a catalytic layer facing the substrate and including a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μm, the average particle diameter being obtained by observation using a scanning electron microscope. Another exhaust gas-purifying catalyst includes a substrate, and a catalytic layer formed on the substrate using slurry containing a precious metal, alumina, an oxygen storage material, and a sulfate of an alkaline-earth metal having an average particle diameter falling within a range of 0.01 to 0.70 μm, the average particle diameter being obtained by observation using a scanning electron microscope.

Exhaust gas purifying catalyst

A catalyst for purifying exhaust gas comprises a honeycomb carrier of monolithic structure and a coating layer deposited on the honeycomb carrier and formed with a catalyst composition containing a refractory inorganic oxide in the form of particles possessing and average particle diameter in the range of 0.5 to 20 microns, which refractory inorganic oxide has platinum and/or palladium and rhodium deposited thereon in high concentrations. This catalyst is produced by coating the honeycomb carrier with an aqueous slurry containing the catalyst composition and calcining the coated carrier.

Catalyst for purifying exhaust gas and method for production thereof

This invention relates to a layered catalyst composition, a process for preparing the composition and processes for using the composition. The catalyst composition comprises an inner core such as alpha-alumina, and an outer layer bonded to the inner core composed of an outer refractory inorganic oxide such as gamma-alumina. The outer layer optionally has uniformly dispersed thereon a platinum group metal such as platinum and a promoter metal such as tin. The composition also optionally contains a modifier metal such as lithium. The catalyst composition shows improved durability and selectively for dehydrogenating hydrocarbons.

Layered catalyst composition and processes for preparing and using the composition

This invention relates to a new catalyst for converting hydrocarbons. The catalyst comprises a platinum group component, a Group IVA component, especially tin, an alkali or alkaline earth component, more than 0.2 weight %, calculated on an elemental basis, of a halogen component and a porous carrier material, wherein the atomic ratio of the alkali or alkaline earth component to the platinum group component is more than 10. The catalyst is particularly useful for dehydrogenating paraffins having from 2 to 5 or more carbon atoms to the corresponding mono-olefins, or for dehydrogenating mono-olefins having from 3 to 5 or more carbon atoms to the corresponding di-olefins.

Dehydrogenation catalyst composition

A monolithic catalyst for purification of exhaust gases is produced by a process which comprises coating a monolithic support with an aqueous slurry composition comprising a powder of active alumina, at least one compound of a platinum-group element selected from the group consisting of platinum, palladium and rhodium, and a powder of cerium hydroxide.

Process for producing monolithic catalyst for purifying exhaust gases

Noble metal catalysts are prepared by supporting a noble metal onto a refractory porous inorganic support from an aqueous medium containing a noble metal or a compound thereof in the presence of a nonionic surface active agent of poly(oxyethylene) type having an average molecular weight of at least 500 and subjecting the so treated support to activation.

Method for the production of noble metal catalysts

PURPOSE:To enhance the purifying action of a ternary catalyst, by forming the platinum group element fixed to activated alumina into an aqueous slurry along with a cerium hydroxide powder and applying said aqueous slurry to a monolithic carrier before additionally applying the other component. CONSTITUTION:At least one of compounds of platinum group elements are supported by an activated alumina powder in a dispersed state to fix at least one of platinum group metals onto activated alumina. This supported platinum group element composition is formed into an aqueous slurry along with a cerium hydroxide powder to prepare a slurry composition which is, in turn, applied to a monolithic carrier. On the other hand, a rhodium compound is supported by an activated alumina powder in a dispersed state to fix rhodium onto activated alumina while the obtained composition is formed into an aqueous slurry which is, in turn, additionally applied to the monolithic carrier, to which the aforementioned coating treatment was applied, to form an exhaust gas purifying catalyst.

Preparation of monolithic type exhaust gas purifying catalyst

PURPOSE:To prepare the titled catalyst having excellent heat resistant durability and low temp. activity, by coating an integral structure type carrier with a slurry composition containing an activated alumina powder, a platinum group element compound and a cerium hydroxide powder. CONSTITUTION:An integral structure type carrier is coated with a slurry composition containing an activated alumina powder, a compound of at least one platinum group element and a cerium hydroxide powder. In this case, the support amount of the cerium hydroxide powder is set to 5-100g/l-catalyst as CeO2 and the particle size thereof is 0.1-0.8mum as a primary particle and 0.3-20mum as a secondary particle and the water content thereof is set to 40wt% or less. As a result, heat resistant durability is enhanced to a large extent as compared with a conventional catalyst using cerium nitrate and low temp. activity is also enhanced.

Ichihara Shoichi

Papers

Process for producing monolithic catalyst for purifying exhaust gases

Method for the production of noble metal catalysts

Preparation of monolithic type exhaust gas purifying catalyst

Preparation of integral structure type catalyst for purifying exhaust gas

Verfahren zur herstellung von edelmetallkatalysatoren