Synthesis and characterization of a novel platinum molybdenum sulfide containing the Mo6S8 cluster

Our previously discovered, low-temperature route for the preparation of ter nary molybdenum sulfide cluster compounds containing the Mo6S8 structure ha s been used to synthesize a new Pt (PtMoS) material. Ion-exchange of amorph ous NaMoS with [Pt(NH3)(4)]Cl-2 led to incorporation of the [Pt(NH3)(4)](2) cation yielding [Pt(NH3)(4)](Mo6S8)S . x(H2O/MeOH), as confirmed by infra red and X-ray photoelectron spectroscopic (XPS) characterization. XPS indic ated that this new platinum material had the reduced molybdenum oxidation s tate characteristic of ternary molybdenum sulfides containing the Mo6S8 str uctural unit. The surface area of the new PtMoS material was as high as 135 m(2)/g. Attempts to convert the PtMoS material to a crystalline Chevrel ph ase PtMo6S8 by H-2 reduction at elevated temperatures were unsuccessful. Ho wever, H-2 treatment at 400 degrees C provided material retaining the Mo6S8 cluster, probably as amorphous Pt(Mo6S8)S. The latter material is a very a ctive hydrodesulfurization (HDS) catalyst, with much higher activity compar ed to other more stable compounds containing the Mo6S8 cluster unit. (C) 20 00 Elsevier Science S.A. All rights reserved.