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

US6713031B2 · kind B2 · utility

Assignee

• DMC2 Degussa Metal Catalysts Cerdec AG · DE

Inventors

• Michael Harris · Hudson, US
• Jurgen Leyrer · Rheinfelden (Baden), DE
• Yvonne Demel · Frankfurt am Main, DE
• Egbert Lox · Hanau, DE
• Thomas Kreuzer · Karben, DE

Key dates

• Filing date: May 9, 2001
• Grant date: Mar 30, 2004
• Expiry date: Nov 21, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

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.