Unsupported PtSn powder was prepared by direct reduction of a solution containing both H2PtCl6 and SnCl4 using hydrazine as the reducing agent. The dark gray powder was characterized with scanning electron microscopy (SEM), EDX analysis, Mössbauer spectroscopy, X-ray diffraction, XPS depth profiling after different treatments: presintering, O2 and H2 treatments. SEM showed a conglomerate of small spherical particles (0.2-1.5 μm). They contained Pt, various PtSn alloy phases and tin-oxide(s). EDX showed 70-75% Pt and 25-30% Sn on various grains. The mixture of Pt3Sn and SnO2 represented the final stabilized state obtained upon repeated heating in air and, finally, H 2. This mixed Pt-Sn was catalytically inactive in "structure-sensitive" reactions, such as methylcyclopentane ring opening or cyclohexane dehydrogenation, but was active in "structure- insensitive" hydrogenation and also in the dehydrogenation of cyclohexene. The relative importance of the latter two reactions depended strongly on the previous treatments of the catalyst - i.e., on its composition, the final stage (Pt3Sn and SnO2) being most active, with cyclohexane as the main product.
- Bimetallic catalyst
- Electron microscopy
- Hydrogenation and dehydrogenation of cyclohexene
- Mössbauer spectroscopy
- X-ray diffraction
ASJC Scopus subject areas
- Process Chemistry and Technology