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Activated carbon fibers (ACFs) were prepared by CO 2 activation of chars obtained by pyrolyzing Nomex [poly ( m -phenylene isophthalamide)], either alone or pre-impregnated with phosphoric acid (impregnation ratio of 7 wt.% H 3 PO 4 ). The resulting materials were characterized by elemental analysis, X-ray diffraction, SEM-EDX, thermogravimetry and N 2 (77 K) and CO 2 (273 K) adsorption. Nomex impregnation with phosphoric acid produced an increase in the char yield in pyrolysis (64.1 vs. 53 wt.% without impregnation) and enhanced the reactivity during activation by an almost sevenfold factor. ACFs with BET surface areas as high as 1300 m g at burn-off degrees of the order of 40% are obtained from both nonimpregnated and impregnated Nomex.

Composite activated carbon monoliths were prepared from polyfurfuryl alcohol-impregnated compressed expanded graphite (CEG) blocks by pyrolysis at 923 K followed by steam activation at 1073 K. The porous texture of these materials was analysed from physical adsorption measurements of N 2 at 77 K and CO 2 at 273 K. Pyrolysis gives rise to a nitrogen surface area higher than for many conventional carbonised precursors of active carbons. Activation develops even more the porosity. At low burn-offs, there is principally creation of new pores (including ultramicropores). At higher burn-offs (of the order of 40%), opening of preexisting pores takes place. The materials obtained are essentially microporous and exhibit a rather narrow pore size distribution.