Effect of crystallization mode of hydrous zirconia support on the isomerization activity of Pt/WO₃-ZrO₂

A series of crystalline hydrous zirconia supports were prepared by different methods. The effects of preparation method of crystalline hydrous zirconia on its crystallization mode and the catalytic activity of Pt/WO ₃-ZrO₂ in n-hexane isomerization were studied. The catalysts were characterized by XRD and Raman spectroscopy, H₂-TPR and NH₃-TPD in order to investigate the crystalline structure, reduction properties and acidity of the catalyst. The results indicated that the crystallization mode of hydrous zirconia from different preparation methods was closely related to the ambience of the process, which significantly influenced the isomerization activity of Pt/WO₃-ZrO₂. The crystallization occurring at the surface region of the hydrous zirconia particles led to an inactive Pt/WO₃-ZrO₂, while the crystallization occurring only inside hydrous zirconia particles led to a catalyst with high activity.