Showing papers on "Noble metal published in 1992"

Hydrogenation catalyst and process

Abstract: The present invention relates to catalysts suitable for hydrogenating aromatics and olefins in hydrocarbon feedstocks boiling between about 125° C and about 625° C as well as the process for carrying out the hydrogenation The catalysts consist of one or more Group VIII noble metal(s) on a support wherein the support is a Y-type zeolite prepared by contacting a starting Y-type zeolite having a unit cell size less than about 2465, preferably less than about 244 angstroms, a silica to alumina molar ratio greater than about 5, preferably by greater than about 25 and an alkali metal content of less than about 030, preferably less than about 015 percent (basis metal) with one or more aqueous solution(s) comprising alkali(ne-earth) metal ions under conditions sufficient to provide a final alkali metal content (measured in terms of gram equivalent weight per gram of zeolite) of at least about 15 times greater than the alkali metal content (measured in terms of gram equivalent weight per gram of zeolite) of the starting zeolite Preferred Group VIII metals are platinum and palladium and sodium is a preferred alkali(ne-earth) metal

Catalytic decomposition of nitrous oxide on metal exchanged zeolites

Abstract: The catalytic decomposition of nitrous oxide to nitrogen and oxygen was studied over a number of catalysts. Copper and cobalt exchanged ZSM-5, mordenite, zeolite beta, ZSM-11 and ferrierite are much more active than other cation-exchanged zeolites (Cu-Y, Co-Y, Co-erionite, Cu-L, Co-L, Ni-ZSM-5, Mn-ZSM-5) and metal oxides (CuO/Al2O3, and CoO/Al2O3). For noble metal catalysts, a cation exchanged ZSM-5 has higher activity than the Al2O3 supported form. Rhodium is the most active catalyst, but surprisingly Pt-ZSM-5 is one of the least active catalysts of all. Also, the effects of oxygen and nitric oxide addition, metal loading, and pretreatment upon the catalyst activity were evaluated.

Catalyst for purifying exhaust gas

Abstract: A catalyst for purifying an exhaust gas, which comprises a first component having the activity for reducing nitrogen oxides with ammonia and a second component having at least one of the activity for forming nitrogen oxide from ammonia and the activity for forming carbon dioxide from carbon monoxide. The first component is formed of a composition containing oxide of at least one member selected from titanium, vanadium, tungsten and molybdenum and the second component is formed of a composition containing a salt of a noble metal selected from platinum, palladium and rhodium or any one of these noble metals preliminarily supported on a porous material selected from zeolite, alumina and silica. A method of purifying an exhaust gas containing NOx, CO and leak NH₃ by the catalyst.

Conducting electrode layers for ferroelectric capacitors in integrated circuits and method

Abstract: A ferroelectric capacitor for an integrated circuit includes a stack formed by a layer of a noble metal, a layer of a conducting oxide, a layer of a ferroelectric material, another layer of a conducting oxide and another layer of a noble metal. The capacitor can also have another layer of conducting oxide located over the top layer of noble metal and below the first layer of the noble metal. A method of forming the same through establishing one layer over the other and annealing each layer is also disclosed.

Fuel cell and method for producing an electrode used therefor

Abstract: In a fuel cell comprising a pair of gas-diffusion electrodes provided with a porous catalyst layer and an acidic electrolyte layer held by the pair of gas-diffusion electrodes, a cathode which constitutes itself one of the pair of gas-diffusion electrodes comprises a heat-resistant and acid-resistant carrier particles and a noble metal catalysts carried on the carrier particles, the surface of the carrier particles and the catalysts being coated with a proton-conductive thin film exhibiting the ability to dissolve and diffuse oxygen and offering resistance to heat and acids or at least the surface of the noble metal catalysts being coated with a thin film which is a polymer network retaining a proton-conductive substance capable of dissolving and diffusing oxygen and resisting heat and acids therein. The proton-conductive thin film of the cathode or the thin film of the polymer network containing the proton-conductive substance is produced by placing an electrode substrate in an electrolytic solution containing a proton-conductive substance alone or in combination with a polymer network material and submitting it to electrolysis therein.

Catalytic oxidation of aqueous organic contaminants

Abstract: A catalyst for oxidizing aqueous organic contaminants includes about 5 wt % to about 20 wt % noble metal crystallites selected from the group consisting of platinum, palladium, ruthenium, iridium, and combinations thereof deposited on a high surface area catalyst support. The crystallites are about 100 Å or smaller. A system for catalytically oxidizing aqueous organic contaminants has a catalyst bed containing such a catalyst, means for heating a reactor feed stream to a desired reaction temperature, means oxygenating the feed stream, and a phase separator for separating gaseous reaction products from a reactor effluent stream.

Structure and method for corrosion and stress-resistant interconnecting metallurgy

Abstract: This invention relates generally to structure and method for corrosion- and stress-resistant interconnecting metallurgy, and more specifically to new structures and methods for corrosion- and stress-resistant interconnecting multilayer metallurgical pad comprising sequentially deposited layers of chromium, nickel and noble or relatively noble metal as the interconnecting metallurgy, or multilayer metallurgical pad comprising sequentially deposited layers of chromium, soluble noble metal, nickel and noble or relatively noble metal as the interconnecting metallurgy. This invention also relates to an improved multilayer metallurgical pad or metallurgical structure for mating at least a portion of a pin or a connector or a wire to a substrate.

Experimental partitioning of osmium, iridium and gold between basalt melt and sulphide liquid at 1300°C

Abstract: The partitioning of Os, Ir and Au between FeNi sulphide liquid and basalt melt was determined at 1300°C and low pressure using internally buffered charges in alumina containers sealed in silica tubes. Six runs were at the oxygen fugacity of the iron‐silica phase‐fayalite (IQF) buffer and one at iron‐wustite (IW), with Os, Ir and Au concentrations in the sulphide ranging from approximately 45 to 400 ppm for each metal. The monosulphide liquid (FeNi) varied from 0.02 to 8.9 at % Ni. The major element composition of silicate glass and sulphide run products was quantitatively determined by electron microprobe analysis. The noble metal content of the sulphide phase was calculated from the initial platinum‐group element (PGE) content added and corrected for dilution by constituents derived from the silicate melt, which was mainly iron. Noble metals in silicate glasses were determined by radiochemical neutron activation. Average distribution coefficients (D) for the IQF buffered runs were D(Os) = 3720 ± 1320, D(...

Catalyst of the galloaluminosilicate type containing gallium, a nobel metal of the platinum family and at least on additional metal, and its use in the aromatization of hydrocarbons

Abstract: A composite catalyst containing: an MFI zeolite in hydrogen form, the framework containing at least one of the elements silicon, aluminium and/or gallium; a matrix; gallium; at least one noble metal of the platinum family, at least one additional metal selected from the group made up to tin, germanium, indium, copper, iron, molybdenum, gallium, thallium, gold, silver, ruthenium, chromium, tungsten and lead, and possibly a compound selected from the group made up of alkali and alkaline earth metals. Its preparation and its use in reactions for aromatising hydrocarbons containing 2 to 9 carbon atoms per molecule.

Mechanism of sulfur poisoning on supported noble metal catalyst — The adsorption and transformation of sulfur on palladium catalysts with different supports

Abstract: A series of supported palladium catalysts (Pd/Al2O3, Pd/MgO and Pd/TiO2) were prepared by the impregnating method and treated with H2S, H2 +O2 or O2, among which H2S is used as a poison and H2 +O2 or O2 are as purging atmospheres. The S2− species in the supports was introduced by means of mechanically mixing Na2S with the supports or catalysts. X-ray photoelectron spectroscopy (XPS) was employed to determine the changes in the chemical states of oxygen, palladium and sulfur in the catalysts before and after the treatment, while infrared (IR) spectroscopy was used to measure the SO2− 4 group produced in the catalysts and supports. The results show that on MgO and TiO2 carriers whose acidities are weak, there exist two kinds of oxygen species, one is the lattice oxygen, the other one is the active species of oxygen. The latter can oxidize the S2− into SO2− 4 even at room temperature in air. Because of the weak acidities and smaller specific surface area of MgO and TiO2, the S2− is liable to adsorb on the catalysts and to transform into SO2− 4. But for the case of Al2O3 support its acidity is rather strong, and its surface oxygen species under the experimental conditions is not so active as that in MgO and TiO2 carries. The poison H2S on the Al2O3 support only experiences a process of physical adsorption-desorption. In Pd/Al2O3 catalyst, the negatively charged sulfur ions are not so easily adsorbed and transformed as those in Pd/MgO and Pd/TiO2. It is also implied that the properties of the carriers are related to the ability of self-regeneration of the corresponding catalysts. Pd/Al2O3 catalyst is more able to self-regenerate than Pd/MgO and Pd/TiO2 catalyst.

Noble Metal Catalyzed Oxidation of Carbohydrates and Carbohydrate Derivatives

Abstract: Summary The oxidation of carbohydrates over noble metals provides an important route towards various interesting compounds. Besides some general information on noble metal catalyzed oxidations an overview of the current state of the art on carbohydrate oxidations is presented. The oxidation of several classes of carbohydrates and derivatives is described and discussed. Also, attention is paid to the mechanism of the formation of sideproducts during the reaction.

A method for separating a water soluble noble metal catalyst from a noble metal catalyzed hydroformylation reaction

Abstract: A method for separating a water soluble Group VIII noble metal catalyst from the crude reaction product of a noble metal-catalyzed hydroformylation reaction run in aqueous solution, in an aqueous emulsion or as an aqueous suspension, the crude reaction product including an aqueous phase containing a water soluble Group VIII noble metal-ligand complex catalyst, and an organic phase containing unreacted olefin feed and an organic hydroformylation reaction product, which comprises: (a) contacting the crude reaction product with a hydrophobic membrane capable of allowing a substantial portion of the unreacted olefin feed and the organic hydroformylation reaction product to pass therethrough while retaining a substantial portion of the water soluble Group VIII noble metal-ligand complex catalyst; (b) removing unreacted olefin feed and organic hydroformylation reaction product which passes through the hydrophobic membrane as permeate; and (c) retaining the water soluble Group VIII noble metal-ligand complex catalyst as retentate.

Multimetallic sulfide catalyst containing noble metals for hydrodenitrogenation

Abstract: The present invention relates to novel catalysts for removing heteroatoms, particularly nitrogen, from hydrocarbonaceous feedstocks. The catalysts are comprised of highly dispersed molybdenum sulfide promoted with a noble metal such that the noble metal is in an oxidation state greater than 0 and coordinated to S. The noble metal is selected from Pt, Pd, Rh, and Ir. It is preferred that the catalysts of be prepared from a precursor composition selected from platinum ethoxyethyl xanthate or platinum dithiocarbamate. Additionally, the catalyst may include a promotor sulfide such as nickel sulfide, cobalt sulfide or iron sulfide, etc. or mixtures thereof.

Catalytic control of air pollution: mobile and stationary sources

Abstract: Catalyst Technologies To Meet Future Emission Requirements for Light-Duty Vehicles Methane Oxidation over Noble Metal Catalysts as Related to Controlling Natural Gas Vehicle Exhaust Emissions Automotive Catalyst Strategies for Future Emission Systems Experimental Comparison Among Hydrocarbons and Oxygenated Compounds for their Elimination by Three-Way Automotive Catalysts Steady-State Isotopic Transient Kinetic Analysis Investigation of CO-O[2 and CO-NO Reactions over a Commercial Automotive Catalyst Particle Size and Support Effects in NO Adsorption on Model Pt and Rh Catalysts Effect of Ce on Performance and Physicochemical Properties of Pt-Containing Automotive Emission Control Catalysts The 1990 Clean Air Act and Catalytic Emission Control Technology for Stationary Sources Selective Catalytic Reduction of Nitric Oxide with Ammonia over Supported and Unsupported Vanadia Catalysts Catalytic Oxidation of Trace Concentrations of Trichloroethylene over 1.5% Platinum on *g-Alkumina Catalytic Oxidation of Trichloroethylene over PdO Catalyst on *g-Al[2O[3 Thermal Decomposition of Halogenated Hydrocarbons on a Cu(111) Surface

Conductive paste composition

Abstract: PURPOSE: To form a smooth burned surface, and to stabilize a resistance value of an electrode to be generated at a low value in the case where both of the noble metal powder and the noble metal coated ceramics powder are used together as a material of conductive paste CONSTITUTION: Noble metal powder and noble metal powder coated ceramics powder are mixed at a weight ratio in a range of 95:5 to 20:80 to form the conductive paste composition The mean grain diameter of the noble metal powder is larger than the mean grain diameter of the noble metal coated with ceramics powder COPYRIGHT: (C)1994,JPO&Japio

IR study of gas-sensor materials: NO interaction on ZnO and TiO2, pure or modified by metals

Abstract: The interaction with NO of differently pretreated ZnO and TiO 2 pressed powders, pure or modified by noble metal addition (Pt and Ru, respectively) is studied, mainly by FT-IR spectroscopy; the analysis of the IR spectra concerns both the vibrational modes of the absorbed species and the variations of the IR transparency related to changes in the electrical properties. The data presented indicate that the NO molecules are dissociated and that electron transfer from the solid to the produced oxygen atoms occurs on prereduced samples, both pure and metal modified; the metal modifiers also adsorb NO in molecular form.

Group IVB oxide addition to noble metal on rare earth modified silica alumina as hydrocarbon conversion catalyst

Abstract: By this invention there is provided a catalyst composition comprising a Group IVB oxide, an amorphous silica-alumina support having dispersed thereon a rare earth oxide, which as herein used also includes yttrium oxide, and a metal(s) selected from the group consisting of Group VIII noble metal(s), mixtures of Group VIII noble metal(s) and tin, mixtures of Group VIII noble metal(s) and rhenium, and mixtures of Group VIII noble metal(s), tin and rhenium. The amorphous silica-alumina support contains at least about 50% silica by weight. The catalyst can function as a hydrocarbon conversion catalyst in reactions where platinum on halided (Cl,F)-alumina is typically used.

Catalyst for decomposition of nitrous oxide

Abstract: PURPOSE:To attain excellent peculiar effects such as a very slight change with the lapse of time as well as to enable efficient catalytic decomposition of N2O in exhaust gas by carrying iridium and at least one among Nb2O5, Tie2 and ZrO2 on a hydrophobic carrier. CONSTITUTION:This catalyst for decomposition of nitrous oxide is a catalyst obtd. by carrying iridium and one or more kinds of oxides selected among Nb2O5, TiO2, and ZrO2. on a hydrophobic carrier such as silica gel, activated alumina or silica-alumina. When this catalyst is produced, the hydrophobic carrier is immersed in an aq. soln. of iridium chloride for a certain time to impregnate the noble metal and the carrier is dried and further immersed in an aq. soln. of one or more among niobium chloride, titanium sulfate and zirconyl sulfate for a certain time to impregnate these precursors of oxides. The carrier is then dried, fired at 300-500 deg.C for 3-5hr and subjected to reduction treatment at 400-500 deg.C for 3-5hr in a flow of gaseous H2.

A New Periodic Displacement Method Applied to Electrodeposition of Cu‐Ag Alloys

Abstract: A new method is described for preparing multilayered alloys by periodically interrupting electrodeposition of the less noble metal to permit electroless displacement of a portion of the electrodeposited material by the more noble component. Visibly smooth, nodule‐free Cu‐Ag alloys of controlled composition have been prepared and shown to exhibit excellent tensile properties. The Ag displacement layers grow epitaxially on Cu(111) planes, which are preferentially aligned parallel with the cathode surface for the cyanide bath studied. In addition, periodic displacement deposition of multilayered structures potentially represents a sensitive means for studying the kinetics of such displacement reactions.

Apparatus for the electrolytic production of metals

Abstract: Improved electrolytic cells for producing metals by the electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells, at least one electrode includes a protective layer comprising an oxide of the cell product metal formed upon an alloy of the cell product metal and a more noble metal. In the case of an aluminum reduction cell, the electrode can comprise an alloy of aluminum with copper, nickel, iron, or combinations thereof, upon which is formed an aluminum oxide protective layer.