Physicochemical characterization and catalytic properties of solid superacids based on sulfated zirconia modified with supported platinum

The acidic properties and electronic state of platinum in superacidic catalysts based on sulfated zirconia are studied by diffuse-reflectance IR spectroscopy. The spectroscopic data indicate a positive charging of platinum microparticles due to the interaction with strong Broensted acid sites, which presumably represent delocalized protons and are characterized by a broad absorption band at similar to 3100 - 2950 cm(-1). For the ZrO2 sample, however, it is likely that a partial negative charge is induced on the metal particle due to the influence of the ZrO2 support which reveals basic properties. The sulfated systems were shown to exhibit high activity and selectivity in n-butane isomerization. Plausible reaction pathways and intermediates are discussed.