Effect of aluminum on the mechanical stress stability of WOx/ZrO2 superacid

Abstract Tetragonal structure of the ZrO 2 support is very important for WO x /ZrO 2 catalysts to be highly active. In this study, it was found that mechanical stress treatments (grinding in a mortar or pressing under 50 MPa) resulted in a partial phase transformation of WO x /ZrO 2 from tetragonal ZrO 2 to monoclinic ZrO 2 and also decreased the n -heptane isomerization activity of the Pt/WO x /ZrO 2 catalyst. The addition of aluminum greatly improved the resistance of WO x /ZrO 2 to mechanical stress and maintained its n -heptane isomerization activity.