The porous network in carbon aerogels investigated by small angle neutron scattering

Small angle neutron scattering treated with the Pored approach has been applied to compare the influence of catalysts (C = NaOH, Na(2)CO(3) and Ca(OH)(2)) on the porous structure of resorcinol-formaldehyde (RF) carbon aerogels. Investigated parameters are the molar ratio (R/C varies from 10 to 800 mol/mol) and the pyrolysis temperature (1050 degrees C, 1700 degrees C and 2600 degrees C). At 1050 degrees C, carbon aerogels based on NaOH and Na(2)CO(3) catalysts provide denser materials than with Ca(OH)(2)-based one, due to a three-dimensional network of smaller particles. The density of particles decreases with the amount of catalyst. At 2600 degrees C the development of an intraparticle microporosity, which is quantified, leads to a slight decrease of the interparticle mesoporosity noticed at 1050 degrees C. This effect is induced by a stiffness of carbon layers in polyhedral pore walls as illustrated by the feature of the chords length distribution g(r) and TEM micrographs. (C) 2007 Elsevier Ltd. All rights reserved.