Characterisation of activated carbon fibers by positron annihilation life-time spectroscopy (PALS)

摘要

The use of Positron Annihilation Lifetime Spectroscopy (PALS) technique to characterize porous carbon materials has been analyzed. Positron annihilation lifetimes have been measured in two series of petroleum pitch-based activated carbon fibers (aCF) prepared by CO_2 and steam activation. Two lifetime components were found: a short-lived component, tau_1 from 375 to 393 ps and a long-lived component, tau_2 from 1247 to 1898 ps. The results have been compared to those obtained by Small Angle X-Ray Scattering (SAXS) and N_2 and CO_2 adsorption at 77K and 273K respectively. The correlation found demonstrates the usefulness of PALS to get complementary information on the porous structure of microporous carbons.