PT-SN AL2P3 CATALYSTS PREPARED WITH NOVEL BIMETALLIC PRECURSORS - CHARACTERIZATION AND CATALYTIC ACTIVITY/

New bimetallic compounds are proposed as models for the preparation of Pt-Sn/Al2O3 reforming catalysts. [Pt(NH3)(4)][SnCl4], [Pt(NH3)(4)][Sn Cl6] and [Pt(NH3)(4)][PtCl2(SnCl3)(2)] have been recently synthesized and characterized by XRD, EXAFS and infrared spectroscopy, The air cal cination of the precursors leads to the formation of platinum clusters and the loss of tin whereas the H-2 reduction gives only the PtSn all oy. The supported samples prepared by formation of the bimetallic prec ursors in the porosity of the carrier show a better (Pt-Sn) interactio n than conventional catalysts obtained by coimpregnation or successive impregnations. This interaction displays low catalytic activity for c yclohexane dehydrogenation and depends on the activation conditions or aging of the catalysts.