ANALYSIS OF POROUS CARBON WITH XE-129, H-1-NMR AND N-2 POROSIMETRY

Activated carbon materials are complex, noncrystalline solids that are difficult to characterize. In this work microstructure within the sample activated carbons has been elucidated by combining the results from Xe-129, H-1 NMR spectroscopy and nitrogen porosimetry. Using the Horvath-Kawazoe model to transform nitrogen physiosorption data the micropore sizes of the carbons were found to be approximately 5.9 angstrom. Evaluation of Xe-19 and H-1 NMR spectra of xenon and adsorbed methane, respectively, provided the chemical shift data necessary to calculate the lateral dimensions of the graphitic microdomains and, hence, those of the pores. By this method, the microdomain sizes were found to vary between 15 and 30 angstrom. These values are in good agreement with the sizes of the microdomains expected based on earlier results provided in the literature that show a range from 15 to 60 angstrom.