A METHOD FOR MEASURING THE TITANIA SURFACE-AREA ON MIXED OXIDES OF TITANIA AND SILICA

We have used temperature-programmed desorption (TPD) and thermogravimetric analysis (TGA) of 2-propanol to characterize several silica, titania, and silica-supported titania samples. Upon evacuation, most of the 2-propanol desorbed intact from the silica samples. This is in contrast to the results on titania and on silica-supported titania, where a significant amount remained on the surface following evacuation, with a fraction of this reacting to propene and water. The coverages of 2-propanol are approximately proportional to the titania surface area, corresponding to between 2.4 and 6.1 x 10(18) molecules/m2 of titania, depending on the form of the titania. The results suggest that selective adsorption of 2-propanol may be useful for determining the surface area of titania in titania-silicates.