Effective ultramicropore volume

Surface coverage of the supermicropore walls is indicated by the appearance of a short linear section at as > 0.5. Extrapolation of this section to as = 0 provides an approximate evaluation of the effective ultramicropore volume, up(u, mic). 

The results in Tables 1 and 2 reveal that the total effective micropore volume, is almost independent of the choice of carbon black and also differences of only a few percent are obtained in the corresponding values of effective ultramicropore volume. However, mueh larger differences are observed if a graphitized carbon is employed as the nonporous reference material. 

By assuming that the density of the adsorbed nitrogen is the same as that of the liquid at 77K, we can arrive at an assessment of the effective micropore volume, Vp(mic), the effective ultramicropore voliune, Vp(u,mic), and the effective supermicropore volume, Vp(s, mic) - the latter being the difference between Vp(mic) and Vp(u, mic). If we assume that surface coverage of the walls of the supermicropores takes place before the onset of the cooperative filling process [1], we can also evaluate the internal area of the supermicropores, a(s,mic). 

Ultramicroporous carbons generally give linear DR plots [7, 11] over wide ranges of p/p°, but the extent of the linear region is much more restricted with most nanoporous carbons [11]. Also, DR plots on many nonporous and mesoporous carbons exhibit similar ranges of linearity [7]. Since D, E, and Mp are all empirical parameters, their significance is questionable. In consequence, it must be emphasized that the simple DR plot cannot always give a true assessment of the effective micropore volume [11]. 

Taking into account that such a perfect correlation with the ultramicropore volume is not so well observed for all kinds of porous carbons [131], it is once more obvious that the electrochemical performance for hydrt en storage is strongly controlled by the presence of mesopores connected to the microporcs. The mesopores are essential to Teed the micropores with hydrated ions or water molecules which will be further reduced giving hydrogen able to be fixed in the ultramicropores. A direct evidence of the beneficial effect of mesopores has been demonstrated by the carbonization of sucrose in the SBA-15 template... 

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