mixed metal oxide composite, method for preparing a mixed metal oxide composite, engine exhaust treatment catalyst, emission aftertreatment system, and method of treating an exhaust stream

摘要

Provided are composites of mixed metal oxides comprising: a ceria-zirconia-alumina composite, wherein the alumina is present in an amount in the range of 1 to less than 30% by weight of the composite and the mixed metal oxide composite has a ceria reducibility of at least 50% after 12 hours of hydrothermal aging at 1050° C. In preparation thereof, a ceria-zirconia solid solution can optionally further comprise at least one rare earth oxide other than ceria and the alumina may be formed by using a colloidal alumina precursor. Methods of making and using these composites are also provided.