United States of America As Represented by the Administrator of Nasa

Airflow Catalyst Systems, Inc.

Jerry C Summers

Suresh Thakordas Gulati

Donald M Oglesby

David R Schryer

Jeffrey D Jordan

Anthony Neal Watkins

Bradley D Leighty

Patricia P Davis

Jacqueline L Schryer

The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages.

Methodology for the effective stabilization of tin-oxide-based oxidation/reduction catalysts

Stabilized tin-oxide-based oxidation/reduction catalysts

A tin-oxide based three-way catalytic material employing precious metals that is stable at exhaust gas temperatures of internal combustion engines when the tin oxide lattice includes any of several rare earth oxide stabilizers in the lanthanide series. The rare-earth elements are the 15 lanthanide elements with atomic numbers 57 through 71 that are in Group IIIA of the Periodic Table: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Such tin-oxide based catalytic materials may also beneficially include zirconium oxide and/or yttrium oxide. The invention is useful in providing three-way catalytic exhaust converters for internal combustion engines.

Tin oxide exhaust catalyst supports and catalysts stable at high temperatures

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Charleston, WV, United States of America

Jerry C Summers