TiO2-ZrO2 mixed oxide as a support for hydrotreating catalyst

Pure TiO2, ZrO2 and TiO2-ZrO2 mixed oxides are prepared by urea hydrolysis. Hydrotreating catalysts containing 12 wt% molybdenum are prepared using th ese oxides and characterized by BET surface area, pore volume, XRD and oxyg en chemisorption. It is observed that oxides produced by the method of urea hydrolysis have higher surface area as compared to those available commerc ially. With increasing zirconia content in the mixed oxide, the surface are a increases and a maximum value is obtained for a mixed oxide having Ti and Zr molar ratio of 65/35. XRD results indicate that mixed oxides are poorly crystalline in nature. Thiophene hydrodesulfurization, cyclohexene hydroge nation and tetrahydrofuran hydrodeoxygenation are taken as model reactions for evaluating catalytic activities. It is found that both O-2 uptake and c atalytic activities increase with increasing zirconia content in mixed oxid e and reach maximum values for the 12 wt% Mo/TiO2-ZrO2 (65/35) catalyst. Wi th further increases in zirconia content, O-2 uptake and catalytic activiti es decrease and the lowest values are observed for the pure ZrO2 supported catalyst.