Gas Adsorption

Gas adsorption is one of many experimental methods available for the surface and pore size characterization of porous materials. These include small angle x-ray and neutron scattering (SAXS and SANS), mercury porosimetry, electron microscopy (scanning and transmission), thermoporometry, NMR-methods, and others. Each method has a limited length scale of applicability for pore size analysis. An overview of different methods for pore size characterization and their application range was recently given by IUPAC [1]. Among these methods gas adsorption is the most popular one because it allows assessment of a wide range of pore sizes (from 0.35 nm up to > 100 nm), including the complete range of micro- and mesopores and even macropores. In addition, gas adsorption techniques are convenient to use and are not that cost intensive as compared to some of the other methods. A combination of mercury porosimetry and gas adsorption techniques allows even performing a pore size analysis over a range from ca. 0.35 nm up to ca. 400 μm.