| abstract |
The present invention relates to diesel oxidation catalyst compositions and catalyst articles, wherein the compositions and articles comprise a plurality of platinum group nanoparticles in substantially fully reduced form, wherein the nanoparticles have an average particle size of from about 1 to about 10 nm and at least about 90 % of nanoparticles have an average particle size +/- a particle size of about 2 nm. Such compositions may further comprise a refractory metal oxide material, wherein the nanoparticles and refractory metal oxide material may be combined within the same coating on the substrate or may be applied sequentially to the substrate. The nanoparticles are advantageously substantially free of halides, alkali metals, alkaline earth metals, sulfur compounds and boron compounds. Also provided herein are methods of making and using such compositions and catalyst articles (eg, for treating diesel exhaust streams). |