Structure and properties of bifunctional catalysts based on zirconia modified by tungsten oxide obtained by polymeric precursor method Original Research Article

Bifunctional catalysts of Pt/WOx–ZrO2 (PWZ) type with 1 wt% of Pt and 10, 15 and 20 wt% of tungsten were synthesized by polymeric precursor method and after they were calcined at 600, 700 and 800 °C. The structural and textural properties of the catalysts were by X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), N2 adsorption measurement, temperature programmed reduction by derivative thermogravimetry (TPR–DTG) and transmission electron microscopy (TEM). X-ray diffractogram revealed the presence of tetragonal ZrO2 and platinum (Pt) as the main phases. The infrared spectra of the catalysts showed bands due O–W–O and Wdouble bond; length as m-dashO bonds. The catalysts showed specific surface area values in the range of 30–160 m2 g−1. TPR profile showed reduction peaks at high temperatures that were related with the reduction of WOx species. Such catalysts were active in the n-heptane isomerization with high selectivity to branched product.