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 N₂ 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 N₂ adsorption isotherm.Both stacking height, Lc and stacking width, La of ACFs began to increase remarkably above 2000 K. The amounts of N₂ 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.