Abstract: A process for the catalytic reduction of NO.sub.x, the reduction taking place in the presence of a catalyst which comprises(a) from 20 to 97 wt % of A.sub.2 O.sub.3,(b) from 1 to 40 wt % of CuO,(c) from 1 to 50 wt % of ZnO,(d) from 1 to 40 wt % of Ag,(e) from 0 to 2 wt % of Pt,(f) from 0 to 20 wt % of oxides of rare earth metals, elements of the 3rd subgroup of the Periodic Table of the Elements or mixtures thereof,based on the total weight of the components (a) to (e), which adds up to 100 wt %, wherein, in each case, up to half the weight of the component (a) may be replaced by Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3, Ga.sub.2 O.sub.3 or mixtures thereof, of the component (b) by CoO, of the component (c) by MgO, of the component (d) by Au and of the component (e) by Pd, Ru, Os, Ir, Rh, Re or mixtures thereof, is used for reducing NO.sub.x, especially in combustion off-gases, the components (a), (b) and (c) forming a spinel which is doped with the components (d), (e) and (f).

Abstract: NO.sub.x, where x is 1 and 2, in exhaust gases is reduced over heterogeneous catalysts with hydrocarbons, carbon monoxide, hydrogen or mixtures thereof in the presence of oxygen from 100 to 650.degree. C. and an absolute pressure of from 0.5 to 50 bar by a process in which the heterogeneous catalysts used are bimodal or polymodal compounds of the general formula IA.sub.1-x M.sub.2 O.sub.4 (I),which, if required, are doped with rare earth metals, noble metal, titanium, vanadium, molybdenum, tungsten or mixtures thereof, and whereA is magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin or mixtures thereof,M is aluminum, gallium, indium, tin, chromium, manganese, iron, cobalt, nickel, copper, zinc or mixtures thereof andx is from 0 to 0.

Abstract: A method of catalytically reducing nitrogen oxides (NO.sub.x) and oxidizing hydrocarbons or carbon monoxide in exhaust gases of internal combustion engines or combustion power plants using a catalyst comprising a magnesium oxide/copper oxide/aluminum oxide spinel or a copper-impregnated copper oxide/aluminum oxide spinel.

Abstract: The present invention relates to a method for operating a catalyst for gases, especially for exhaust gases of stoichiometrically operated gasoline engines, wherein a catalyst is exposed to a gas stream and pollutants are catalytically converted. To improve the elimination of pollutants in the starting phase, hydrocarbons present in the gas are temporarily stored by the catalyst at temperatures below a response temperature of the catalyst, particularly below 200.degree. C., and preferably below 150.degree. C. The hydrocarbons are then released at temperatures above the response temperature and the pollutants, such as nitrogen oxides, are catalytically converted with reducing agents, such as hydrocarbons, carbon monoxide and mixtures thereof. The catalyst is a spinel, such as (MgCu)Al.sub.2 O.sub.4, which may also include a catalytically active species, such as WO.sub.3, V.sub.2 O.sub.5 and TiO.sub.2.

Abstract: The present invention relates to a method for operating a purification device, to a purification device and to the use of same. To reduce the emission of pollutants, a filter body through which a fluid can flow and comprising a catalyst, is exposed to a stream of gas which is to be purified. Before the gas enters the catalyst, a reducing agent is added in the flow direction of the gas, and after a certain treatment point, during which the gas, which is to be purified, is flowing in the catalyst, reducing agent is added once more to the flowing gas by a feeding mechanism and contact with the catalyst is maintained.

Abstract: The invention relates to a method and a device for cleaning flowing gases. To reduce the total emissions, nitrogen oxides, especially NO and NOx, are extracted at least partially from the gas to be scrubbed, in the temperature range from 50 and 300.degree. C., preferably between 50 and 150.degree. C. To extract the nitrogen oxides, an intermediate storage medium is used that is composed of a storage material and a supporting material for the storage material. The intermediate storage medium having in particular a composition of the formal chemical formula Ag.CuAl.sub.2 O.sub.4 in an Al.sub.2 O.sub.3 matrix, with the composition being a spinel or being of the spinel type, and with the composition having characteristic spinel lines in the x-ray spectrum, where 0.ltoreq.x<1.

Abstract: A catalyst and a method for producing the catalyst, for catalytic reduction of NO.sub.x and oxidation of hydrocarbons, the catalyst comprises a zinc, copper and aluminum spinel to which, at least one element selected from palladium, platinum, rhodium, ruthenium, osmium, iridium, rhenium and/or rare earth metals, such as lanthanum and cerium, vanadium, titanium, niobium, molybdenum, tungsten and/or salts thereof and/or oxides thereof has been added.

Abstract: A catalyst and a process for producing the catalyst are provided. For the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons, the catalyst contains a spinel containing the metals copper, zinc and aluminum.

Abstract: A method operates an improved internal combustion engine by heating the fuel before entry into the cylinder, at least during the cold-start phase of the engine. In order to undertake the heating step in a favorable way, at least areas in the region of an intake valve are irradiated with an electromagnetic radiation of radiation source, and thereby heated without contact. As a result, liquid fuel in the valve region is heated by contact with the areas of the valve region, and condensation of the fuel is at least reduced.

Abstract: A catalyst and a method for producing the catalyst, for catalytic reduction of NO.sub.x and oxidation of hydrocarbons, the catalyst comprises a zinc, copper and aluminum spinel to which, at least one element selected from palladium, platinum, rhodium, ruthenium, osmium, iridium, rhenium and/or rare earth metals, such as lanthanum and cerium, vanadium, titanium, niobium, molybdenum, tungsten and/or salts thereof and/or oxides thereof has been added.

Abstract: A material and a process for adsorbing and desorbing nitrogen oxides in exhaust gas systems of engines running on a lean mixture, which does not require a prior oxidation step, wherein a mixed oxide which has an oxygen-rich orthorhombic structure is used which changes to an oxygen-poor tetragonal structure as a function of temperature.

Abstract: An organic layer for subsequent coating with a cover layer which is harder than the organic layer, and a process for surface treatment of the organic layer. In order to improve the quality of a subsequently applied cover layer, growth nuclei for the cover layer, which exhibit sp.sup.2 and/or sp.sup.3 bonding orbital hybridization, are arranged and/or exposed on the free surface of the organic layer.

Abstract: A layer construction with an organic layer and a transparent cover layer which covers the organic layer and which is harder than the organic layer, and a process for producing such a layer construction in which the cover layer is deposited on the surface of the organic layer from a precursor material present in the gas phase. In order to improve the optical quality of the layer construction, the cover layer, at least in a transition region between the organic layer and the cover layer, is deposited with an index of refraction which differs by a maximum of 20%, in particular by a maximum of 10%, from the index of refraction of the underlying organic layer.

Abstract: A catalyst and a process for producing the catalyst are provided. For the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons, the catalyst contains a spinel containing the metals copper, zinc and aluminum.

Abstract: A method for catalytically reducing pollutants, in particular oxides of nitrogen in oxygen-containing exhaust gases of internal combustion engines, uses a catalyzer unit arranged in the exhaust gas flow of the engine. The catalyzer unit has a catalytic layer, an ion conducting layer and a counterelectrode. The catalytic layer exhibits a non-Faraday modification of the catalytic activity.

Abstract: A description is given of superconducting substances having a content of Bi, Sr, Ca and Cu, and of processes for their preparation from the metal oxides within a range which is specified by the overall composition Bi.sub.a (Sr,Ca).sub.b -Cu.sub.6 O.sub.x, where a=3-24 and b=3.23-24, with an Sr/Ca atomic ratio of 1:9-9:1 and a Bi:(Ca+Sr) atomic ratio of 0.3-1.5. The transition temperature is at least 60 K. The principal phase crystallizes in the orthorhombic system. The pure compounds Bi.sub.4 (Sr,Ca).sub.4 Cu.sub.2 O.apprxeq..sub.12 and Bi.sub.4 (Sr,Ca).sub.6 Cu.sub.4 O.apprxeq..sub.20.

Abstract: A layer construction with an organic layer and a transparent cover layer which covers the organic layer and which is harder than the organic layer, and a process for producing such a layer construction in which the cover layer is deposited on the surface of the organic layer from a precursor material present in the gas phase. In order to improve the optical quality of the layer construction, the cover layer, at least in a transition region between the organic layer and the cover layer, is deposited with an index of refraction which differs by a maximum of 20%, in particular by a maximum of 10%, from the index of refraction of the underlying organic layer.

Abstract: An organic layer for subsequent coating with a cover layer which is harder than the organic layer, and a process for surface treatment of the organic layer. In order to improve the quality of a subsequently applied cover layer, growth nuclei for the cover layer, which exhibit sp.sup.2 and/or sp.sup.3 bonding orbital hybridization, are arranged and/or exposed on the free surface of the organic layer.

Abstract: The invention provides a catalyst, and a process for preparing the same, for the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons. The catalyst contains a copper oxide-zinc oxide-aluminum oxide spinel and a zeolitic support material.