INFLUENCE OF AN FE PROMOTER ON SILICA-SUPPORTED PT SNOX CATALYSTS USED FOR LOW-TEMPERATURE CO OXIDATION/

Silica-supported Pt/SnOx catalysts used for low-temperature CO oxidati on have been prepared without and with an Fe promoter. Reaction studie s demonstrate that the addition of the Fe promoter results in higher c atalytic activity in the presence of 8 at% CO2 and a lower decay rate. Ion scattering spectroscopy (ISS) has been used to examine the outerm ost atomic layers of the promoted and nonpromoted catalysts before and after activation by a reductive pretreatment. The nonpromoted catalys t exhibits agglomeration of the platinized tin oxide film exposing the catalytically inactive silica support. This agglomeration does not oc cur when Fe is present, and a large catalytically active surface area is maintained during the reduction.