Effect of Acid-Base Properties on the Catalytic Activity of Pt/AlO Based Catalysts for Diesel NO Oxidation.

The activity of Pt catalysts supported on AlO modified with various acid-base additives has been investigated for oxidation of NO to NO. Although Pt dispersion was changed by the additives, there was no clear effect of Pt dispersion on the catalytic activity. The measurement of solid acid-base properties of the modified Pt/AlO indicated that the NO oxidation activity increased by the increase of surface density of strong acid sites and decreased by the increase of basic sites. It was suggested that platinum on the acidic supports keeps its highly active metallic state for NO oxidation, while the formation of nitrate/nitrite on the basic supports inhibits the reaction on the Pt surface. [ABSTRACT FROM AUTHOR]