The application of small angle scattering techniques to porosity characterization in carbons

Small angle scattering (SAS) techniques offer a number of advantages for the investigation of the nature and behavior of porous materials. In particular, with respect to carbons, the essentially non-intrusive nature of SAS means that along with the more traditional, pre- and post-treatment characterization of carbons, in principle, characterization can also be performed in situ during adsorption and activation processes. In the current communication, the application of the techniques of small angle X-ray (SAXS) and neutron (SANS) scattering is reviewed specifically with respect to porosity characterization in carbons. First, the basis of these techniques is presented. More recent applications of SAXS and SANS to carbon porosity are presented, and their relative attributes are contrasted, including the related technique of contrast matching with SANS to distinguish "closed" from "open" porosity, and its application to elucidation of pore development mechanisms. Applications of other related techniques, such as μSAXS and TGA/SAXS, to carbon characterization and porosity development are also discussed