Characterization of bimetallic PtSn catalysts supported on purified and H2O2-functionalized carbons used for hydrogenation reactions

The state of the metallic phase of PtSn/C catalysts prepared by coimpregnat ion and successive impregnation on purified and H2O2-functionalized carbons as supports was studied by TPD, TPR, H-2 chemisorption, XPS, and test reac tions. Furthermore, the characteristics of the metallic structures were rel ated with the catalytic behaviors in the selective hydrogenation reaction o f carvone in liquid phase. In PtSn/C samples, most of the Sn would be in in timate contact with Pt, and the surface of the reduced bimetallic catalysts would be composed of metallic platinum, Sn(II), and/or Sn(IV) species, and small amounts of zerovalent tin, probably forming alloys with Pt-0. The hi gh selectivity of these bimetallic PtSn/C catalysts for the production of u nsaturated alcohols in the reaction of carvone hydrogenation would be due t o the action not only of the promoter (Sn) but also of the support (carbon) . (C) 1999 Academic Press.