Influence of Preparation Conditions on the Acidity of WO<sub>3</sub>/ZrO<sub>2</sub> Solid Superacid

WO 3 /ZrO 2 solid superacid catalysts were prepared by coprecipitation and impregnation, then were characterized by XRD, N 2 adsorption-desorption, Hammett indicator and pyridine chemisorption IR. The acid strength, acid type, acid volume, etc were compared under the different preparation conditions. The results indicated that the catalyst prepared by coprecipitation had stronger acid strength than the catalyst prepared by impregnation. The samples prepared by impregnation had more Lewis acid sites. With the increasing of the W/Zr ratio, the acid strength tended to increase at first and then decrease, and the catalyst with 10% WO 3 loading amount had the strongest acidity. The higher the calcination temperature, the less the Lewis acid sites.