초록 ▼

Alumina supported platinum-group metal pelleted catalysts are made which exhibit excellent performance and which have unique Pt concentration profiles. The catalysts are doubly promoted with ceria and alkali metal oxides, especially ceria along with lithia, and can optionally have nickel (oxide) as

Alumina supported platinum-group metal pelleted catalysts are made which exhibit excellent performance and which have unique Pt concentration profiles. The catalysts are doubly promoted with ceria and alkali metal oxides, especially ceria along with lithia, and can optionally have nickel (oxide) as a base metal catalytic ingredient. The unique Pt profile is obtained by adding at least part of the Rh component separately from any other Pt group metals.

대표청구항 ▼

A catalyst suitable for use as a three-way catalyst for auto emission control comprising an alumina pelleted support having deposited thereon 1-20% by weight of ceria as a promoter, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytially-effective amount of one

A catalyst suitable for use as a three-way catalyst for auto emission control comprising an alumina pelleted support having deposited thereon 1-20% by weight of ceria as a promoter, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytially-effective amount of one or more platinum group metals comprising at least platinum and rhodium, said platinum group metals penetrating the alumina support to an average distance less than approximately 300 microns as measured by the SnCl2 solution staining method, said platinum having a platinum concentration curve as function of depth which is concave down, i.e., having a second derivative of the mathematical expression describing the concave-down segment of the curve which is not greater than zero, from the surface down to a point of inflection for the curve.