Mixed phase oxide catalysts

摘要

An emission control catalyst for treating an engine exhaust includes non-precious metal group (“NPGM”) mixed phase oxide catalyst having a mullite phase containing optionally in close contact with other metal oxides. The mixed phase catalyst may be included in one or more layers or zones of a multi-layered or multi-zoned emission control catalyst and optionally in combination with precious metal catalysts such as Pt, Pd and Au.

主权项

1. An engine exhaust catalyst, comprising:
a fluorite phase containing a cerium oxide; a spinel phase containing a metal oxide; and a mullite phase; wherein the catalyst has the general formula:
Ce1−xAx+aBy+bMz−yOs where:
M is one or more metal elements selected from the group consisting of transition metals;A is one or more metal elements selected from the group consisting of transition metals, poor metals, and the Lanthanide series, wherein A and M are different metals;B is one or more metal elements selected from the group consisting of alkali metals and alkaline earth metals;
x is a number defined by 0≦x<1,a is a number defined by a≧−1,y and z are numbers defined by 0≦y≦z,b is a number defined b≧0, ands is a number that renders the catalyst substantially charge neutral.