Method of preparing a double layered, palladium-only three-way catalyst
AssigneeHyundai Motor Company
InventorGwon Koo Yeo
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Abstract
The present invention relates to a method of preparing a double layered, palladium-only three-way catalyst using three different composite oxides. More particularly, the present invention relates to a method of preparing a double layered, palladium-only three-way catalyst comprising a first coating layer (bottom layer) and a second coating layer (top layer) containing palladium by incorporating composite oxide, praseodymium oxide, and perovskite.
Claims16
A method of preparing a double layered, palladium-only three-way catalyst comprising the steps of:
- preparing a first catalyst slurry and a second catalyst slurry using palladium, alumina, cerium oxide and a mixing solution;
- first coating of the first catalyst slurry on a ceramic monolith substrate;
- drying the substrate;
- calcining the substrate;
- and
- second coating of the second catalyst slurry:
- wherein said first catalyst slurry is prepared by adding 15 to 25 g/L of a mixture of cerium oxide, cerium—zirconium composite oxide [(Ce.Zr)O2] and cerium—zirconium—yttrium composite oxide [(Ce.Zr.Y)O2], proportions of which ranging from 25:60:15 to 20:60:20 by weight, with respect to the total apparent volume of the substrate to alumina;
- adding 2 to 5 g/L of praseodymium oxide with respect to the total apparent volume of the substrate;
- and adding 15 to 25 g/L of metal oxide (perovskite) selected from (LaCe)(FeCo)O3 and (LaSr)(FeCo)O3 with respect to the total apparent volume of the substrate.
A method of reducing automobile exhaust emission components comprises using a double layered, palladium-only three-way catalyst having a substrate, a bottom layer with a ternary composite oxide disposed over said substrate, and a top layer with palladium disposed over said bottom layer.
Dependencies are inferred from the claim text.