Showing papers on "Noble metal published in 1980"

Noble metal-chromium alloy catalysts and electrochemical cell

Abstract: A novel and improved noble metal-chromium alloy catalyst is disclosed with catalytic oxygen reduction activity at least twice that of the unalloyed noble metal. The noble metal-chromium alloy catalyst disclosed has particular utility as an electrocatalyst for the reduction of oxygen which makes it particularly useful as a cathode catalyst in an acid fuel cell.

The electrocatalytic oxidation of methanol in acid electrolyte: preparation and characterization of noble metal electrocatalysts supported on pre-treated carbon-fibre papers

Abstract: The electrocatalytic aspects of direct oxidation of methanol in acid electrolyte in relation to fuel cell applications is briefly reviewed. The reaction requires noble metal catalysts (in particular platinum) in large quantities (several mg cm−2 of electrode area) to produce steady state current densities of commercial interest. Initial activities are about 104 times greater than steady state values, thus the problem in methanol electro-oxidation is to stabilize the initial activity.

Fabrication of electrical conductor by replacement of metallic powder in polymer with more noble metal

Abstract: A low-cost conductor, e.g. a printed circuit, is prepared by applying a mixture of a metallic powder and polymer on a substrate and curing the polymer, followed by an augmentation replacement reaction being effected to replace some of the metallic powder with a more noble metal in such a way that the total volume of deposited metal on the surface exceeds that of the original metal powder at that surface. This procedure produces contiguous layer of conducting metal on the substrate. The conductors thus formed can easily be soldered without leaching using a conventional tin-lead solders.

O 2 Electrocatalysis on Thin Film Metallic Oxide Electrodes with the Delafossite Structure

Abstract: Thin film electrodes of , , , and delafossite‐type oxides are good electrocatalysts for reduction and evolution in. reduction activity correlates with the noble metal cation , while evolution activity correlates with the transition metal cation . Electrodes were prepared by rf sputtering from metal alloy targets. The as‐sputtered films are amorphous. The delafossite phase forms on annealing in air or at 700°–850°C. Thin films are metallic with .

Diesel exhaust catalyst

Abstract: A catalyst which is particularly useful in the treatment of diesel exhaust emissions is described. The catalyst comprises a mixture of a supported noble metal and/or chromium component and a bulk first transition series, silver, and/or hafnium component. The supported component catalyzes hydrocarbon conversions and the bulk component catalyzes combustion of carbon particulates in diesel exhaust gases.

II. XPS study of 3d-metal ions dissolved in noble metals

Abstract: Valence and core level spectra ofAgMn,AuFe,AuCo,AuNi,CuFe,CuCo andCuNi will be reported. Clearly defined virtual bound states (vbs) can only be detected in the spin fluctuating systemsAuNi andCuNi. An increase in the density of states near the Fermi energy, in the region of the flats-p band of the host metal is observed in the other magnetic alloys. There are indications that a large hybridization between the impurity and the host metald-electrons exist. The impurity core levels show satellites. They can originate from the emission from real isolated impurities and from many body effects.

Aromatics processing catalysts

Abstract: A method of preparing aromatics processing catalysts which comprises incorporating a noble metal with a member or members of a useful class of zeolites, with such incorporation occurring after zeolite crystallization, but prior to final catalyst particle formation, i.e. extrusion into particles. Said useful class of zeolites is characterized by a silica to alumina mole ratio of at least 12 and a Constraint Index in the approximate range of 1 to 12.

Hydrocarbon conversion catalyst system and method

Abstract: A hydrocarbon conversion catalyst system comprising a mixture of a first catalyst containing a noble metal component deposed on a refractory inorganic oxide and a second catalyst containing a non-noble metal component deposed on a support containing a refractory inorganic oxide and a crystalline aluminosilicate material, and a reforming method employing such catalyst system are disclosed.

Metal Filmed‐Semiconductor Photoelectrochemical Cells

Abstract: Voltammetric and light to electrical energy conversion characteristics of metallized semiconductor Schottky junctions with redox solution contacts are reported. Electrodeposited noble metal films on establish contacts to reversible aqueous redox couple solutions that can sustain solar photocurrent levels with low loss, requiring only a thin metal layer adequate to photovoltaic barrier formation. Possible advantages in lateral conductivity, relative to solid‐state Schottky devices, and in surface stability and redox electrolyte independence, relative to semiconductor‐liquid junction solar cells, are weighed against both the absorptive losses in the metal layer and the practicalities of obtaining sufficient integrity in the film to serve the semiconductor corrosion protection function. Gold, platinum, and rhodium plated with carbon counter‐electrodes and ferro‐ferricyanide solutions give 2–6% conversion efficiency under solar irradiance.

Spark plug and the process for production thereof

Abstract: A spark plug with a spark electrode prepared by mixing at least a matrix material of a titanium compound (e.g., TiO2, TiC, TiN, etc.) with an electrical conductivity-imparting substance (e.g., Pt and Pd, or a mixture of Pt, Pd and a noble metal, e.g., Au, Ru, Ag, Rh, etc.) and sintering the resulting mixture.

Simultaneous determination of the noble metals in geological material by radiochemical neutron-activation analysis

Abstract: A simple procedure is described for determining the noble metals in geological samples rich in chromium and copper. Powdered rock samples (0.1–0.3 g) are irradiated in an epithermal neutron flux, under a cadmium filter, to reduce interference from 51Cr and 64Cu. After digestion with a peroxide fusion, the noble metals are separated on Srafion NMRR ion-exchange resin. Activity from chromium(VI), retained on the resin, is eliminated by reduction to chromium(III) with iron(II) sulphate before separation. The gamma-ray activity is measured with a lithium-drifted germanium detector for palladium (109Pd), platinum (199Au), iridium (194Ir) and gold (198Au). The separation yield (iridium 40%, palladium 80%, gold 90%) is determined for each sample by irradiating the resin to activate a stable noble metal carrier. Multi-element noble metal standards (0.1–8 µg) are prepared from dilute solutions (100 µl) evaporated on resin (1 ml). The practical detection limits are 2.5 ng of palladium and platinum, 0.1 ng of iridium and 0.01 ng of gold. The reliability of the procedure was confirmed by analysing sulphide standards (PTM, PTC) and standard rocks (PCC-1, DTS-1). The method has been applied to the analysis of chrome-spinels.

Preparation of vinyl acetate from ethylene, acetic acid and oxygen in the gaseous phase

Abstract: The carriers contain common active components, namely noble metals of the 8th sub-group or compounds thereof, and as activators alkali metal compounds, alkaline earth metal compounds or cadmium compounds. The carriers, too, consist of common materials, such as silicic acid. A novel feature is to be seen in the shape of the carrier particles which are designed as rod sections having a star-shaped cross section (FIGS. 1 to 7) or as ribbed rods (FIG. 8). In relation to the apparent density and thus in relation to the amount of noble metal employed, a considerably higher space-time yield is reached than with carrier particles of a conventional shape.

Corrosion resistant amorphous noble metal-base alloys

Abstract: An amorphous alloy is prepared by rapid quenching from the liquid state and consists of (1) 10 to 40 atomic percent of P and/or Si (2) 90 to 60 atomic percent of two or more of Pd, Rh and Pt. The amorphous alloy is used for an electrode for an electrolysis.

Process for selective dealkylation of alkyl-substituted aromatic hydrocarbons

Abstract: In a process for dealkylating a hydrocarbon material containing at least one alkyl-substituted aromatic hydrocarbon having bonded to the aromatic ring at least one alkyl group with at least 2 carbon atoms in the gaseous phase in the presence of hydrogen using a hydro-dealkylation catalyst, the improvement wherein (a) said hydro-dealkylation catalyst is composed of a crystalline aluminosilicate having a silica/alumina mole ratio of from 20 to 200 and containing a noble metal selected from platinum, palladium, rhodium and iridium, and (b) said dealkylation is carried out at a temperature of 250° C. to 420° C. and a pressure of not more than 100 psig, thereby selectively removing said alkyl group containing at least 2 carbon atoms from said alkyl-substituted aromatic hydrocarbon.

Oxygen content exhaust gas sensor, and method of its manufacture

Abstract: To improve operation and output voltage, particularly at 400° C. and less, an oxygen sensor, especially adapted to determine oxygen content of automotive exhaust gases, is constructed by utilizing two electrodes applied on a body of stabilized zirconium dioxide, for example a closed tube, by making an electrode exposed to the exhaust gases in form of a mixture of finely dispersed ceramic material and a platinum-rhodium alloy, the ceramic material being present at about 40% (by volume) and 60% (by volume) platinum-rhodium alloy of 50-94% platinum and 50-6% rhodium (by weight). The second electrode, exposed to a reference gas comprises an alloy of palladium and another noble metal in a ratio of about 19-90% (by weight) Pd and 81-10% (by weight) noble metal. This electrode may also contain up to 40% (by volume) finely dispersed ceramic material. The electrode exposed to the exhaust gases is covered with a porous coating. The electrodes can be applied as aqueous or organic solutions of soluble noble metal compounds or suspensions, colloidal suspensions, with organic solvents, and the like, and subsequent sintering.

Preparation of noble metal catalyst

Abstract: PURPOSE: To uniformly disperse noble metal particles onto a carrier, by conjunctly using carbon powder as the carrier when a noble metal solution is mixed with a protective colloid and reacted with a reducing agent. CONSTITUTION: To obtain a nobel metal catalyst, especially a catalyst suitable as an electrode in a fuel battery, a reducing agent, e.g., methanol, is mixed with water and a protective colloid, e.g., PVA, is dissolved in the mixture. To the mixed solution is added a noble metal ion or its complex salt, e.g., a chloroplatinic acid solution, and then carbon powder, e.g., acetylene black. Thereafter, the solution is heated and reacted, to obtain a platinum catalyst supported on the acetylene black. The protective colloid inhibits the coagulation of the noble metal particles, and improves their dispersion state. The carbon powder facilitates fine uniform dispersion of the noble metal particles. COPYRIGHT: (C)1981,JPO&Japio

Catalyst for reforming of methanol

Abstract: PURPOSE:To obtain a long-lived catalyst having a high activity even at low temperatures as a catalyst for reforming methanol by supporting a base metal, e.g., Cu, Zn, etc., and a noble metal, e.g., Pt, etc., on an alumina support already covered with zirconia. CONSTITUTION:As a catalyst for reforming methnaol into a gas containing hydrogen and carbon monoxide, a catalyst obtained by supporting a base metal, e.g., Cu, Zn, etc., or oxides of these, and a noble metal, e.g., Pt, Pd, etc., on an alumina support already covered with zirconia is used. The catalyst can exhibit a high catalytic activity even at comparatively low temperatures when being used in reforming of methanol, and also the deterioration of its activity at high temperatures is less and exhibit a high catalytic actvity.

Gas sensitive devices

Abstract: Catalytic gas sensors comprise a noble metal filament onto which is applied alumina having a particle size of not greater than 100 A and a catalyst material is impregnated into the dried alumina. The alumina may be dried by passage of an electric current through the filament and, prior to coating the filament may be stabilized by coating with a thermally decomposable aluminium salt and decomposed by passing a pulsed electric current.

Recovery and use of fission product noble metals

Abstract: Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value. (DLC)

All solid state electrode system

Abstract: A cell body having a pair of electrodes insulated from each other and adapted for direct immersion and use in commercial, laboratory, or industrial fluids or process streams, the cell being usable at temperatures below freezing and above the boiling point of water. The cell includes an insulated ultra pure antimony electrode and an insulated electrode of noble metal, the noble metal of the one electrode being immersed in the process stream as is the pure antimony electrode. The cell provides a self-contained solid state unit with the two electrodes adapted to measure pH in fluids or process streams containing solid mineral or ore particles, in acid, neutral or basic solutions of a wide range of temperatures and pressures, including vacuum applications and this system requires no external or internal reference or standard electrodes. The self-contained all solid-state electrode system is connected directly to the proper electronic circuitry, either nearby or remote to produce a signal or display pH or its equivalent. The pure antimony electrode and its insulation extend into the process stream a further distance than does the noble metal electrode, and the insulation for the noble metal electrode extends beyond the noble metal end thereof.

Effects of implantation in rutile with metallic ions

Abstract: Rutile single crystals (TiO2) have been implanted with heavy metallic particles in the energy range 0.3 MeV, 56 MeV. Optical measurements have been performed during implantation. Conductivity and Rutherford backscattering measurements have been made on as-implanted samples and after thermal treatments. With alkali ions implanted in TiO2 the optical spectra exhibit an absorption band associated with a transition of titanium 3+ state after irradiation. The conductivity of the implanted layer increases by a factor of the order of 107 after implantation with a dose of 1017 particles per cm2. Thermal treatments of these samples do not permit to obtain metallic absorption of alkali aggregates like in magnesium oxide. These results confirm the hypothesis of chemical bonding between alkali ions and oxygen correlated to the formation of Ti3+. With noble metal ions, like silver or gold implanted in TiO2, the optical spectra exhibit optical absorption of small metallic aggregates of silver or gold. The abso...

Dehydroformylation of steroidal aldehydes

Abstract: The invention relates to a process for dehydroformylation of dinorcholanaldehydes and dinorcholenaldehydes to form 17(20)-pregnenes or 20-pregnenes. The dehydroformylation is carried out using a noble metal catalyst, and preferably carried out in the presence of a hydrogen acceptor.

Stainless steel plated with noble metal

Abstract: PURPOSE: To improve surface characteristics such as corrosion resistance, electrical connecting property, solderability or the like by interposing the intermediate plating layer of a specific metal or an alloy between a noble metal plating layer and stainless steel. CONSTITUTION: After the surface of stainless steel is activated, an intermediate layer comprising one or more of Zn, Cd, Sn, In or an alloy thereof is formed by plating. If necessary, on said plated layer, further, a secondary intermediate layer comprising one or more of Ni, Co or an alloy thereof is provided and noble metal plating such as Au, Ag, Pt or the like is applied thereon. Because said first intermediate layer is less noble than stainless steel in an electrolytic corrosion system, said stainless steel is subjected to cathode corrosion proofing. Further, the secondary intermediate layer prevents deterioration of the noble metal acting as a diffusion barrier. Therefore, the resultant noble metal plated stainless steel is suitable for a material for an electronic and an electric parts. COPYRIGHT: (C)1982,JPO&Japio