Abstract: The present invention relates to a method for manufacture of silver-based composite powders for electrical contact materials. The invention relates also to electrical contact materials made from such composite powders. The process comprises a high energy dispersing process of wet silver oxide (Ag2O) with additional second oxide components in aqueous suspension. The high energy dispersing process can be conducted by high shear mixing or by high energy milling. Preferably high speed dispersing units working at rotating speeds in the range of 5,000 to 30,000 rpm or high energy mills such as attritor mills are used. The new process is versatile, economical and offers access to a broad spectrum of contact materials. The silver-based composite powders made according to the new process yield contact materials with a highly dispersed microstructures and superior material characteristics.

Abstract: The invention relates to the field of electrochemical cells and fuel cells, more specifically to polymer-electrolyte-membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC). A multi-layer membrane-electrode-assembly (ML-MEA) comprising two electrically conductive bipolar plates and a membrane-electrode-assembly (MEA) bonded together by means of an electrically insulating adhesive material is disclosed. The adhesive material, preferably a polyurethane-based system, is in direct contact with the protective film layers attached to front side and the back side of the MEA, thus contamination of the ionomer membrane and/or the electrode layers with adhesive components is avoided. Multi-layer MEAs with improved long term stability and life time are obtained. The products are used for the manufacture of low temperature PEMFC and DMFC stacks.

Abstract: The invention relates to novel monocarbene complexes of nickel, palladium or platinum with electron-deficient olefin ligands, to their preparation and to their use in the homogeneous catalysis of organic reactions.

Abstract: When a nitrogen oxide storage catalyst is being regenerated, the regeneration may be terminated for example as a result of a premature load change in the engine, which can lead to incomplete emptying of the storage catalyst. The residual filling level which remains in the catalyst following an incomplete regeneration of this nature is used as the starting value for calculation of the filling level during the next storage phase. After incomplete regeneration, the nitrogen oxide conversion rate is initially greater than would be expected, on account of the residual filling level. By taking this increased conversion rate into account when calculating the filling level during the storage phase, it is possible to further improve the accuracy of the calculation.

Abstract: An oxygen storage material comprising cerium oxide and at least one second oxide of a metal M1 is disclosed as well as a process for manufacturing the material and the use of this material in an exhaust gas cleaning catalyst. In a preferred embodiment the oxygen storage material comprises particles from a Ce/M1 mixed oxide solid solution coated with an oxide of another metal M2. Metal M1 e.g. can be calcium or zirconium while metal M2 most preferably is aluminum.

Abstract: This invention relates to a method of operating a catalyst for treating the exhaust gas of an internal combustion engine, the catalyst comprising, in addition to catalytically active noble metals, also storage components for storing hydrocarbons. During engine operating phases at low exhaust-gas temperatures, such a catalyst stores the hydrocarbons contained in the exhaust gas without burning them. When the exhaust-gas temperature rises, these hydrocarbons are desorbed again and then oxidized at the catalytically active noble metals. This process can lead to uncontrolled, vigorous combustion of the hydrocarbons stored on the catalyst and, therefore, damage to the catalyst. According to the invention, this damage is avoided by continuously calculating the respective loading of the storage components with hydrocarbons and repeatedly regenerating the storage components depending on the loading by temporarily raising the exhaust-gas temperature before damage to the catalyst can occur.

Abstract: Compounds of the formula (I), in which R1 is C1-C4alkyl, C6-C10aryi or C7-C11, aralkyl, R2 is an open-chain or cyclic secondary amino group, and R is a radical of the formula in which R3 is C1-C4alkyl or C1-C4alkoxy, and R4 is H, C1-C4alkyl or C1-C4alkoxy, are ligands for metal complexes as homogeneous hydrogenation catalysts for prochiral organic compounds containing double bonds, by means of which a very high activity and productivity and also enantioselectivity can be achieved

Abstract: This invention provides a method of regenerating a diesel particulate filter in an exhaust-gas purification system of a diesel engine using lambda variation. During regeneration on demand, the ratio of air to fuel for the corresponding operating point of the diesel engine is adjusted so as to achieve the substantially highest possible exhaust-gas temperature. For this purpose, the ratio of air to fuel (lambda value) is preferably kept at a minimum and substantially constant over the major part of the load range so that the engine is operated at full load during the regeneration phases.

Abstract: An oxygen storage material based on cerium oxide with at least one other oxide of the metals silicon and zirconium, wherein the cerium oxide and the other oxides are present in the form of a mixed oxide. The material is obtainable in that hydroxidic precursors of the mixed oxide are first prepared in a manner known per se using a wet-chemical route, these precursors are optionally dried at temperatures between 80 and 300° C. and the dried precursors are then treated under a hydrogen-containing atmosphere at a temperature between 600 and 900° C. for a period of 1 to 10 hours. The reductive thermal treatment endows the material with a greatly improved dynamic behavior as compared with conventional calcination in air.

Abstract: The present invention describes an exhaust-gas purification system for an internal combustion engine made of an oxidation catalyst arranged close to the engine, a subsequent hydrocarbon adsorber and a particulate filter arranged downstream thereof and provided with another oxidation catalyst. The oxidation catalyst ensures that emission limits with respect to carbon monoxide and hydrocarbons are satisfied in normal driving mode. During operating states with exhaust-gas temperatures below about 200° C., the oxidation catalyst can no longer oxidize carbon monoxide and hydrocarbons. Instead, the hydrocarbons are adsorbed by the hydrocarbon adsorber during these operating phases. In order to initiate the periodical regeneration of the particulate filter, the exhaustgas temperature of the internal combustion engine is raised by engine modifications.

Abstract: The invention relates to a catalyst arrangement for purifying the exhaust gases of internal combustion engines operated under lean conditions. It is proposed that a thinwalled, porous carrier be coated on one side with a nitrogen oxide storage catalyst and on the other side with an SCR catalyst. When the exhaust gas is passed through the catalytic coatings and the support material, a significant improvement in the nitrogen oxide conversion is achieved compared to a series arrangement of the catalysts on separate carriers. Wall flow filters have been found to be useful as thin-walled carriers.

Abstract: The present invention relates to an exhaust-gas purification system for the selective catalytic reduction of nitrogen oxides. The system includes at least one catalyst having catalytically active components for the selective catalytic reduction (SCR components). An NOx storage catalyst (5) is arranged upstream of the SCR catalyst (3) in the exhaust-gas purification system. For performing the selective catalytic reduction, metering means (8) for supplying a compound decomposable into ammonia is provided between the NOx storage catalyst and the SCR catalyst (3). At low exhaust-gas temperatures, the NOx storage catalyst (5) adsorbs the nitrogen oxides contained in the exhaust gas and desorbs them only at rising exhaust-gas temperatures, so that they can afterwards be converted by the SCR catalyst (3) which is active then. This results in an altogether improved conversion rate for the nitrogen oxides.

Abstract: The present invention relates to a mandrel for producing glass tubes or rods, particularly for the Vello process, the A-drawing process and preferably for the Danner process. The mandrel comprises a body (1) of a ceramic composite material, and an external metal material jacket (2) surrounding at least a portion of said body, wherein the ceramic composite material has a substantially similar thermal expansion coefficient as the metal material of said jacket Alternatively the mandrel comprises a self-supporting metal material jacket (22).

Abstract: An oxygen storage material comprising cerium oxide and at least one second oxide of a metal M1 is disclosed as well as a process for manufacturing the material and the use of this material in an exhaust gas cleaning catalyst. In a preferred embodiment the oxygen storage material comprises particles from a Ce/M1 mixed oxide solid solution coated with an oxide of another metal M2. Metal M1 e.g. can be calcium or zirconium while metal M2 most preferably is aluminum.

Abstract: The invention provides a multistep process for preparing a low-sulfur reformate gas for use in a fuel cell system. The process comprises catalytic steam reforming of a reactant gas mixture comprising sulfur-containing hydrocarbons and steam in a first step to make a reformate, reducing the carbon monoxide content of the reformate in a second step, passing the reformate over a sulfur absorber either directly after the first step or after passage through the second step, and desorbing the sulfur components optionally absorbed on the catalysts in the reforming and reducing process steps by periodically raising the temperature so as to cause the sulfer components to pass to the absorber, wherein the temperature of the absorber during operation of the process is always kept within a temperature interval which is an optimum for the absorber.

Abstract: The present invention relates to a method of removing nitrogen oxides from the exhaust gas of a lean-burn internal combustion engine by selective catalytic reduction (SCR) using ammonia. The exhaust gas is routed first over a platinum-containing pre-catalyst and then over an SCR catalyst. The ammonia needed for the selective catalytic reduction is added to the exhaust gas upstream of the pre-catalyst at an exhaust-gas temperature below 250° C., while it is supplied to the exhaust gas between the pre-catalyst and the SCR catalyst at an exhaust gas temperature above 150° C. By adopting this procedure, a very large temperature range for the selective catalytic reduction with high nitrogen conversion rates is obtained.

Abstract: The invention relates to a method and an apparatus of operating a drive system comprising an engine and an exhaust gas purification unit containing a catalyst, where the engine emits an exhaust gas having an exhaust gas temperature and the catalyst has a catalytic activity for the purification of the exhaust gas. In the method, an aging-induced decrease in the catalytic activity of the catalyst is compensated at least part of the time by increasing the exhaust gas temperature of the engine.

Abstract: The present invention provides a catalyst system that may be used to regenerate NOx adsorber catalysts. It also provides methods for using these catalysts. According to the present invention, hydrocarbons are introduced into an exhaust gas stream upstream of a metal ion exchanged zeolite catalyst to generate CO. The metal ion exchanged zeolite catalyst is preferably a Cu-ZSM-5 catalyst that has a high loading of copper. The hydrocarbons are oxidized to carbon monoxide, and the carbon monoxide is then exposed to a NOx adsorber catalyst, which facilitates regeneration of that catalyst.

Abstract: The invention relates to a catalyst and a process for the autothermal, catalytic steam reforming of hydrocarbons using the catalyst. The catalyst has a multilayer structure and comprises a lower catalyst layer located directly on a support body and an upper catalyst layer located on the lower catalyst layer, with the lower catalyst layer preferentially catalysing the partial oxidation and the upper catalyst layer preferentially catalysing steam reforming. In a further embodiment, a three-layer catalyst having a further catalyst layer for the carbon monoxide conversion (water gas shift reaction) is described. Each catalyst layer comprises at least one platinum group metal on an oxidic support material. The steam reforming process is carried out in an adiabatic process by passing a feed mixture of hydrocarbons, oxygen and water or water vapour which has been heated to a preheating temperature over the multilayer catalyst.

Abstract: The present invention relates to the field of electrochemical cells and fuel cells, more specifically to polymer-electrolyte-membrane (PEM) fuel cells and describes a process for the manufacture of membrane-electrode-assemblies (MEAs) containing five layers. The five-layer MEA is assembled together by means of a lamination process involving an adhesive component. The anode gas diffusion layer, the catalyst-coated membrane and the cathode gas diffusion layer are combined together by a low temperature/low pressure lamination process. Handling of the MEAs and assembly of the products into PEMFC and DMFC stacks is simplified. Less damage and perforation of the catalyst-coated membrane occurs and thus the performance of the five-layer MEAs is significantly improved.