Degussa Aktiengesellschaft

Degussa - Huls Ag

Dmc2 Degussa Metal Catalysts Cerdec Ag

Dmc2 Degussa Metals

J&uuml;rgen Leyrer

Thomas Kreuzer

Egbert Lox

Rainer Domesle

Carsten Plog

Wolfgang Strehlau

Thomas Stengel

Harald Klein

Yvonne Demel

Renato Andorf

Michael Harris

Klaus Ostgathe

Norbert Markert

Hans Van Den Tillaart

Wilfried M&uuml;ller

A structured catalyst for selective reduction of nitrogen oxides with ammonia using an ammonia-supplying compound. The catalyst is preferably used for exhaust gas treatment of diesel vehicles powered by diesel motors. The catalyst is characterized by the fact that it contains a reduction catalyst for selective reduction of nitrogen oxides with ammonia and a hydrolysis catalyst for the hydrolysis of urea, where the hydrolysis catalyst is applied in the form of a coating onto the reduction catalyst. By this arrangement of the two catalytic functions in one catalyst the exhaust gas system can be made very compactly and space saving. Moreover, advantageous synergistic effects result from the direct contact of the hydrolysis catalyst and the reduction catalyst.

Structured catalysts for selective reduction of nitrogen oxides by ammonia using a compound that can be hydrolyzed to ammonia

A catalyst for reducing nitrogen oxides in oxidizing and reducing atmospheres which contains iridium on a support material. Silicon dioxide or a dealuminized zeolite in the acid H form with a modulus of more than 20, preferably more than 100, or mixtures thereof are used as support materials. Iridium is deposited on the external surfaces of these support materials with average particle sizes between 10 and 30 nm. The catalyst is particularly suitable for treating exhaust gases from lean-burn gasoline engines or from diesel engines.

Catalyst for reducing nitrogen oxides in oxidizing and reducing atmospheres

A process for preparing a catalyst which has a catalytically active coating of high surface area finely divided materials and catalytically active components on an inert carrier structure. A powder mixture of the finely divided materials used is impregnated with a solution of precursor compounds of the catalytically active components. By suitable combination of the finely divided materials and the precursor compounds and appropriate management of the impregnation process, a highly dispersed deposition and adsorption of the catalytically active components is ensured on the finely divided materials. Then ai aqueous coating dispersion is produced using the impregnated powder mixture and the carrier structure is coated therewith. The coating is then dried and calcined.

Process for preparing a catalyst

A catalyst system for the treatment of exhaust gases from a diesel engine includes a first and a second catalyst reducing catalyst arranged in series in an exhaust gas treatment system. The first catalyst is located near the engine in a region of the exhaust gas treatment system in which the exhaust gas temperature reaches temperatures of more than 200&deg; C. under full engine load. The second catalyst is located further from the engine in a region of the exhaust gas treatment system in which the exhaust gas temperature reaches a maximum of 500&deg; C. under full engine load. The maximum nitrogen oxides reduction in the first catalyst takes place at a lower temperature than the maximum nitrogen oxides reduction in the second catalyst.

Catalyst system for the treatment of exhaust gases from diesel engines

Growing community of inventors

Rheinfelden, Germany

Jürgen Leyrer

Growing community of inventors

Rheinfelden, Germany

J&uuml;rgen Leyrer

Jürgen Leyrer