STRUCTURE AND PROPERTIES OF WO_3-ZrO_2 GEL COMPOSITES AS POTENTIAL CATALYSTS FOR HYDROCARBONS ISOMERIZATION PROCESS

摘要

Tungsten oxide dispersed on zirconia in WO_3-ZrO_2 system found application as strong acidic catalyst in hydrocarbons isomerization process. Specific method for synthesis of gel metal oxide composites based on Complex Sol-Gel Process (CSGP) were elaborated in Institute of Nuclear Chemistry and Technology, Warsaw. Structural investigations of WO_3-ZrO_2 gel composites thermally treated at 500°C, 650°C and 800°C using X-ray diffraction (XRD) and scanning electron microscopic (SEM) methods were carried out. The gel composites annealed at 500°C appears as amorphous material, in the composites thermally treated at 650°C beginning of crystalline forms are observed. The gel composites annealed at 800°C are polycrystalline. Both oxides exist as separate crystalline phases, ZrO_2 in the high symmetry forms: cubic and tetragonal, WO_3 in the monoclinic form.