Exhaust gas treatment catalyst for internal combustion engines with two catalytically active layers on a carrier structure

US6348430B1 · kind B1 · utility

Assignee

• Degussa AG · DE

Inventors

• Dieter Lindner · Hanau, DE
• Renee Van Yperen · Weesp, NL
• Lothar Mussmann · Offenbach, DE
• Egbert Lox · Hanau, DE
• Thomas Kreuzer · Karben, DE

Key dates

• Filing date: Jun 19, 1998
• Grant date: Feb 19, 2002
• Expiry date: Jun 19, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S502/514
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

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. By providing the platinum group metal in close contact with all of the constituents of the first catalytically active layer, improved conversion efficiency of the impurities in the exhaust gas c…