Characterization of tungsten oxide supported on TiO2 and activity for acid catalysis

Abstract

Tungsten oxide-titania catalysts were prepared by drying powdered Ti(OH)4 with ammonium metatungstate aqueous solution, followed by calcining in air at high temperature. Characterization of prepared catalysts was performed by using FTIR, Raman, XPS, XRD, and DSC and by measuring surface area. Upon the addition of tungsten oxide to titania up to 20 wt%, the specific surface area and acidity of catalysts increased in proportion to the tungsten oxide content due to the interaction between tungsten oxide and titania. Since the TiO2 stabilizes the tungsten oxide species, for the samples equal to or less than 20 wt%, tungsten oxide was well dispersed on the surface of titania, but for the samples containing 25 wt% or above 25 wt%, the triclinic phase of WO3 was observed at calcination temperature above 400 °C. The catalytic activities for 2-propanol dehydration and cumene dealkylation were correlated with the acidity of catalysts measured by ammonia chemisorption method.