Structural Characterization of Heat-Treated Activated Carbon Fibers

Pitch (PIT) and cellulose (CEL)-based activated carbon fibers (ACFs) were heated at 1473-3173 K under an Ar atmosphere. The N(2) adsorption, X-ray diffraction (XRD), and magnetic susceptibility of the heat-treated ACFs were measured. The specific surface area of ACF samples was determined by the subtracting pore effect (SPE) analysis using the N(2) adsorption isotherm. Both stacking height, Lc and stacking width, La of ACFs began to increase remarkably above 2000 K. The amounts of N(2) adsorption on PIT and CEL became nil by heating above 1773 K and 2073 K, respectively. The relationships between the heating temperature and the magnetic susceptibility of ACFs near room temperature were divided into three regions: below 1773 K, from 1773 K to 2473 K, and above 2473 K. The results from gas adsorption, X-ray diffraction and magnetic susceptibilities have been explained with respect to the changes taking place in these three regions.