A simple FTIR technique for estimating the surface area of silica powders and films

A simple technique using FTIR spectroscopy to estimate the surface area of porous and non-porous silica powders is presented. The surface area is estimated by comparing the integrated area of the band due to isolated silanol groups on different silicas. We have found that by using a fumed silica as a calibrant, an accuracy of about 7% in the surface area of several silica materials is obtained when compared to the surface area computed by BET nitrogen adsorption techniques. The FTIR technique for computing surface area is simple and takes very little time to complete the analysis. The principle advantage of this method is that it enables surface area measurements of silica films on porous supports. To the best of our knowledge, there are no other methods that provide this information. (c) 2005 Elsevier Inc. All rights reserved.