Dispersion enhanced pt group metal catalysts and method of making the

Abstract

A method of making a three-way catalyst based on platinum group metals, comprisng: (a) impregnating an alumina substrate with a platinum group metal ion by contacting such substrate with an aqueous solution containing the platinum group metal in an amount of 0.1-5% by weight of alumina substrate and a water soluble acid that forms RCOOH with R being an alkyl or equivalent, said acid being present in an amount of 10-120% by weight of the alumina substrate, the pH of said solution being less than 4.0; and (b) drying and calcining the wetted substrate without sintering said substrate. The three-way catalyst construction based on platinum group metals has enhanced catalytic activity. It comprises an alumina substrate and a platinum group metal impregnation layer thereover, said impregnation layer being comprised of raft-like particle structures, each having increased metal density resulting from the nesting of both small and large metal particles within a given volume.