The Effects of Al2O3 Addition and WO3 Modification on Catalytic Activities of NiO/TiO2 for Acid Catalysis

NiO/Al2O3–TiO2/WO3 catalysts for acid catalysis were prepared by the addition of Al2O3 and the modification with WO3. The strong acid sites were formed through the bonding between dispersed WO3 and TiO2. The larger the dispersed WO3 amount, the higher both the acidity and catalytic activity. The addition of Al2O3 up to 5 mol% enhanced acidity and catalytic activity of NiO/Al2O3–TiO2/WO3 gradually due to the interaction between Al2O3 and TiO2 and consequent formation of Al–O–Ti bond. The presence of NiO may attract reactants and enhance the local concentration of reactants near acid sites and consequently increase catalytic activity.