Low-temperature CO oxidation over new types of Sn-Pt/SiO2 catalysts

Sn-Pt/SiO2 catalysts prepared by using controlled surface reactions are hig hly active in the low-temperature oxidation of CO. The results indicate tha t the high activity of these catalysts can be attributed to (i) the stabili zation of tin-platinum alloy phases on the silica support, and (ii) the for mation of "Sn4+-Pt" ensemble sires during the oxidation of CO. It is sugges ted that Sn4+ species formed in situ are involved in the activation of the CO molecule adsorbed at the neighboring Pt site. This activation strongly r esembles that of the carbonyl group in unsaturated aldehydes over this type of Sn-Pt/SiO2 catalysts. (C) 2000 Academic Press.