Abstract: An oxygen storing material with high thermal stability is disclosed which contains cerium oxide and at least one stabilizer from the group praseodymium oxide, lanthanum oxide, yttrium oxide and neodymium oxide, wherein the stabilizer(s) and optionally cerium oxide are present in highly dispersed form on the specific surface area of a high surface area support material from the group aluminum oxide, zirconium oxide, titanium oxide, silicon dioxide, cerium oxide and mixed oxides thereof and the oxygen storing material still has a specific surface area of more than 20, preferably more than 30 m2/g, after calcination in air at 900° C. for a period of 10 hours.

Abstract: A single layer high performance catalyst containing on an inert carrier body a catalytic coating comprising platinum, rhodium and various oxide materials. The catalyst contains a catalytic coating having at least one first support material selected from the group having a first active alumina, a ceria rich ceria/zirconia mixed oxide and a zirconia component, said at least one first support material being catalyzed with a first part of the total platinum amount of the catalyst, and a second support material catalyzed with the second part of the total platinum amount and with rhodium said second support material being a second active alumina.

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: 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: A starter catalyst for the purification of the exhaust gases from internal combustion engines, which include palladium on aluminum oxide and of barium oxide, as well as a process for its production. The barium oxide and palladium are together deposited in a finely divided state on the supporting material aluminum oxide and the average particle size of the palladium crystallites is between 3 and 7 nm. The small crystallite size of palladium and the barium oxide likewise deposited in finely divided state on the supporting material impart to the catalyst a high activity and long-term stability to high temperature stresses.

Abstract: A catalyst for treating the exhaust gas from internal combustion engines is provided, wherein the catalyst contains two catalytically active layers supported on a support. The first catalytically active layer contains a platinum group metal in close contact with all of the constituents of the first catalytically active layer, wherein the constituents of the first catalytically active layer include particulate aluminum oxide; particulate oxygen storage material, such as cerium oxide, cerium/zirconium and zirconium/cerium mixed oxides, and alkaline earth metal oxides. The second catalytically active layer, which is in direct contact with the exhaust gas, contains particulate aluminum oxide and at least one particulate oxygen storage material, such as cerium oxide, cerium/zirconium and zirconium/cerium mixed oxides. Rhodium is supported on part of the aluminum oxides in the second catalytically active layer or on the particulate oxygen storage material in the second catalytically active layer.

Abstract: A process for operating an exhaust gas treatment device in a gasoline engine which is operated mainly with a stoichiometric air/fuel ratio and is operated with a rich-mix air/fuel ratio when accelerating or under full load. The exhaust gas treatment device contains a three-way converter catalyst and a first lambda probe upstream of the catalyst and a second lambda probe downstream of the catalyst. The air/fuel ratio is controlled by using the signal from the first lambda probe, whereas the signal from the second lambda probe is used to check the first lambda probe (trim control) and to diagnose the function of the catalyst. Trim control with the second lambda probe is enabled only when, in the event of rich exhaust gas, the voltage difference between the probe voltage for the second lambda probe and a set point voltage is not larger than a predetermined value.

Abstract: A single layer high performance catalyst containing on an inert carrier body a catalytic coating comprising platinum, rhodium and various oxide materials. The catalyst contains a catalytic coating having at least one first support material selected from the group having a first active alumina, a ceria rich ceria/zirconia mixed oxide and a zirconia component, said at least one first support material being catalyzed with a first part of the total platinum amount of the catalyst, and a second support material catalyzed with the second part of the total platinum amount and with rhodium said second support material being a second active alumina.

Abstract: A catalyst for treating exhaust gas from an internal combustion engine includes a carrier body coated with an inner layer and an outer layer. The inner layer includes platinum deposited on a first support material and on a first oxygen storage component, and the outer layer includes platinum and rhodium deposited on a second support material and on a second oxygen storage component. The first and second support materials may be the same or different, and may be selected from the group of: silica, alumina, titania, zirconia, mixed oxides or mixtures thereof, and zirconia-rich zirconia/ceria mixed oxide. The first and second oxygen storage components may include ceria-rich ceria/zirconia mixed oxide compounds, optionally including praseodymia, yttria, neodymia, lanthana or mixtures thereof.

Abstract: A single-layered three-way catalytic converter containing palladium as the only catalytically active noble metal, with high activity and heat resistance. The catalyst contains, in addition to finely divided, stabilized aluminum oxide, at least one finely divided cerium/zirconium mixed oxide and optionally finely divided nickel oxide as well as highly dispersed amounts of cerium oxide, zirconium oxide and barium oxide. The palladium is distributed largely uniformly throughout the entire catalyst.

Abstract: A method of depositing catalytically active components on high-surface carrier materials is disclosed by dispersing the carrier materials in water and mixing this dispersion with an aqueous solution of soluble precursors of the catalytically active components. The pH of the dispersion is adjusted to a value between 6 and 8 before the aqueous solution of the precursors is supplied by capillary injection under constant agitation of the dispersion and thereafter, if necessary, the precursors of the catalytically active components are precipitated on the carrier material by capillary injection of a dilute base.

Abstract: An exhaust gas purification catalyst with improved hydrocarbon conversion is disclosed, which contains metals from the platinum group as its catalytically active components. Two superposed functional layers are applied to one support. The catalyst has a first functional layer with a mixture of a first catalyst with at least one zeolite and the second functional layer applied to the first functional layer which contains a mixture of a second catalyst and at least one zeolite. The zeolites exhibit a molar ratio of silicon dioxide/aluminum oxide of more than 40 and in that at least palladium and rhodium are present as the platinum group metals and are each contained separately from one another in only one of the two catalysts. The catalyst is distinguished by particularly good suppression of hydrocarbon emissions during cold-starting and exhibits particularly good long-term stability.

Abstract: A catalyst for purifying the exhaust gases from diesel engines. The catalyst contains a zeolite mixture of several zeolites with different moduli and platinum group metals as well as further metal oxides from the group aluminum silicate, aluminum oxide and titanium oxide, wherein the aluminum silicate has a ratio by weight of silicon dioxide to aluminum oxide of 0.005 to 1 and the platinum group metals are deposited on only the further metal oxides.