Abstract: The invention provides platinum or platinum alloy powders for use in fuel cells and for chemical reactions. The powders are characterized by a high surface area and, at the same time, low chlorine contents. The powders are prepared by forming a melt which contains, as starting substances, a low melting mixture of alkali metal nitrates, a chlorine-free platinum compound and optionally chlorine-free compounds of alloying elements, the melt is then heated to a reaction temperature at which the platinum compound and the compounds of alloying elements thermally decompose to give oxides, the melt is then cooled and dissolved in water and the oxides or mixed oxides formed are converted into platinum or platinum alloy powders by subsequent reduction. Binary or ternary eutectic mixtures from the LiNO3—KNO3—NaNO3 system are suitable as a low melting mixture of nitrates of the alkali metals. Hexahydroxoplatinic-(IV)-acid is preferably used as a chlorine-free platinum compound.

Abstract: The invention provides an acid bath for the electrodeposition of glossy gold and gold alloy layers and a gloss additive for same. By using compounds of the formula I R—SOm—H  (I) in which m is the number 3 or 4 and R represents a straight-chain or branched or cyclic alkyl group with up to 20 carbon atoms and, in the event that m=4, also an aryl or heteroaryl group with up to 10 carbon atoms, which may be optionally substituted once or several times with straight-chain or branched alkyl groups with 1 to 14 carbon atoms, as a further gloss additive, the current density/working range is extended with a small negative effect when the pH is changed and the current efficiency and deposition performance is increased.

Abstract: A method is presented in which an active element, e.g. a semiconductor device, is embedded in a passive circuitry formed on a low-cost substrate, having good dielectric properties. After forming the active element on a first substrate, the active elements are singulated and transferred to a second substrate. The active element is bonded to this second substrate and the portion of the first substrate, on which this active element is created, is removed selectively to the active element and the low-cost substrate. On this second substrate passive circuitry may be present or it can be formed after the attachment of the active element. The passive circuitry is interconnected to the active element or other components or dies present on the low-cost substrate.

Abstract: A gas diffusion structure for polymer electrolyte fuel cells having a sheet-like carbon substrate made hydrophobic and having two main opposing surfaces and a contact layer on one of these surfaces. The contact layer is formed of an intimate mixture of at least one hydrophobic polymer, which can be polyethylene, polypropylene or polytetrafluoroethylene, and finely divided carbon particles, wherein the weight percentage of the carbon particles relative to the total weight of the contact layer amounts to 40 to 90 wt. %. The gas diffusion structure is a carbon substrate made hydrophobic by at least one hydrophobic polymer and the hydrophobic polymers are restricted to two layers extending from both opposing surfaces into the carbon substrate down to a depth of from 5 to 40 &mgr;m and the hydrophobic polymers fill of from 20 to 60% of the pore volume within those layers.

Abstract: The invention provides a process for preparing a platinum-ruthenium catalyst and the catalyst prepared therewith. The catalyst can be supported on a support material in powder form or may also be unsupported. To prepare the supported catalyst, the support material is suspended in water and the suspension is heated to at most the boiling point. While keeping the temperature of the suspension the same, solutions of hexachloroplatinic acid and ruthenium chloride are then added to the suspension, then the pH of the suspension is increased to a value between 6.5 and 10 by adding an alkaline solution and the noble metals are thus precipitated onto the support material. Afterwards, one or more organic carboxylic acids and/or their salts are added to the suspension and the catalyst is chemically reduced, washed, dried and optionally subsequently calcined under an inert or reducing atmosphere at a temperature between 300 und 1000° C.

Abstract: The present invention provides an exhaust gas treatment unit for an internal combustion engine. A first catalyst unit produces ammonia from corresponding constituents in a rich exhaust gas composition. A second catalyst unit that is located downstream of the first catalyst unit temporarily stores the ammonia produced by the first catalyst unit in the presence of a rich exhaust gas composition. In the presence of a lean exhaust gas composition, the nitrogen oxides present in the exhaust gas are subjected to a reduction reaction using the temporarily stored ammonia as reducing agent. The exhaust gas treatment unit also contains a third catalyst unit that is located between the other two catalyst units, and oxidizes the nitrogen oxides present in the exhaust gas at lean exhaust gas conditions to a such an extent that 25 to 75 vol. % of the nitrogen oxides entering the second catalyst unit consist of nitrogen dioxide.

Abstract: The present invention provides a process for regenerating the catalytic activity of catalysts that have oxidizing functions. A catalyst that is located in the exhaust gas line of a diesel engine that preferably contains a catalytically active coating on a honeycomb carrier that does not have a filter function and that has at least one oxidizing function is regenerated. As a result of time-restricted increases in the exhaust gas temperature upstream of the catalyst to a value greater than 450° C., the combustion of soot particles and hydrocarbons deposited on the catalyst is initiated, and thus, the catalytic activity of the catalyst is at least partly regenerated.

Abstract: A process is provided for operating a three-way catalyst that contains an oxygen storage component, that has a minimum and a maximum filling degree for oxygen and that is located in the exhaust gas line of an internal combustion engine. The air/fuel mixture supplied to the engine is varied in such a way that the filling degree of the oxygen storage component in the catalyst is held within a set-point interval between the minimum and maximum filling degree. According to this process, in order to regulate the air/fuel mixture, migration of the filling degree out of the set-point interval is checked in a test phase in such a way that the filling degree is increased or lowered relative to the instantaneous value (initial value) by short-term enrichment or reduction in richness of the air/fuel mixture supplied to the engine by a certain amount and immediately returned to the initial value by a short-term opposing change in the air/fuel mixture (lean/rich pulse sequence or rich/lean pulse sequence).

Abstract: A method of producing a semiconductor layer onto a semiconductor substrate. The method comprises providing a first semiconductor substrate, and providing a second semiconductor substrate. The method also comprises producing a porous layer, which has a porosity profile, on top of the first semiconductor substrate, and producing a porous layer, which has a porosity profile, on top of the second semiconductor substrate. The method further comprises bringing the porous layer of the second substrate into contact with the porous layer of the first substrate, so as to form a bond between the two substrates, performing a thermal annealing step, and lifting off of the second substrate, leaving a layer of the second substrate's semiconductor material attached to the first substrate.

Abstract: A method is presented in which an active element, e.g. a semiconductor device, is embedded in a passive circuitry formed on a low-cost substrate, having good dielectric properties. After forming the active element on a first substrate, the active elements are singulated and transferred to a second substrate. The active element is bonded to this second substrate and the portion of the first substrate, on which this active element is created, is removed selectively to the active element and the low-cost substrate. On this second substrate passive circuitry may be present or it can be formed after the attachment of the active element. The passive circuitry is interconnected to the active element or other components or dies present on the low-cost substrate.