BIMETALLIC PT-ZN CATALYSTS SUPPORTED ON ACTIVATED CARBON Joaqun Silvestre-Albero 1 , Juan Carlos Serrano, Antonio Sepœlveda-Escribano, Francisco Rodrguez-Reinoso Laboratory for Advanced Materials, Department of Inorganic Chemistry, Universidad de Alicante, Apartado 99, E-03080 Alicante, SPAIN Corresponding author e-mail address:asepul@ua.es Introduction The modification of the catalytic behavior of a noble metal through the addition of a second non-active metal able to form alloy phases or intermetallic compounds with the former is an interesting field in heterogeneous catalysis. As an example, the platinum-tin system supported on alumina is widely used in naphta reforming and alkane dehydrogenation reactions, where it shows higher activity and stability than the monometallic platinum catalysts [1]. Other important applications of bimetallic Pt-Sn catalysts include the dehydrogenation of light alkanes [2], the oxidation of carbon monoxide [3] and the selective hydrogenation of alfa,beta-unsaturated aldehydes (acrolein, crotonaldehyde, etc.) to yield saturated alcohols [4,5]. For this latter reaction it has been shown that the catalytic performance depends on the Sn/Pt atomic ratio, the preparation method and, mostly, on the interaction between platinum and tin species, both in the metallic and in oxidized states. The Pt-Zn system resembles in some aspects the Pt-Sn system. Platinum and zinc can also form alloy phases of different stoichiometries (PtZn, Pt 3 Zn, among others). In fact, promising results have been obtained with bimetallic Pt-Zn catalysts in reactions such as selective hydrogenation [6]. This communication reports the preparation, characterization and catalytic performance of bimetallic Pt-Zn catalysts with high zinc content supported on activated carbon. Carbonaceous materials are being more and more frequently used as catalyst supports; besides the beneficial contribution of their high surface area, their chemical inertness favors the interaction between the two metallic phases in bimetallic systems as the one under study. Experimental The support was a commercial activated carbon (Norit RX-3, from Norit) with a BET surface area (N 2 , 77 K) of 1350 m 2 •g -1 . Three bimetallic Pt-Zn catalysts were prepared by sequential impregnation. Firstly, the support was impregnated with an aqueous solution of zinc (II) nitrate; samples with nominal contents of 1, 3, and 5 wt% Zn were prepared. After drying, a second impregnation was carried out with an acetone solution of H 2 PtCl 6 of the appropriate concentration to load 0.5 wt% Pt. A monometallic Pt catalyst was prepared in a similar way for the sake of comparison.