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

• Published in: Carbon (New York) Vol. 45; no. 6; pp. 1185 - 1192
• Main Authors: Cohaut, N., Thery, A., Guet, J.M., Rouzaud, J.N., Kocon, L.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-05-2007; Elsevier Science
• Subjects: Chemistry; Colloidal state and disperse state; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General and physical chemistry; Materials science; Physics; Porous materials; Specific materials; Aerogels; Small angle neutron scattering; Carbon; Porous materials
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2007.02.020

Small angle neutron scattering treated with the Porod approach has been applied to compare the influence of catalysts (C
=
NaOH, Na
2CO
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
°C, 1700
°C and 2600
°C).
At 1050
°C, carbon aerogels based on NaOH and Na
2CO
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
°C the development of an intraparticle microporosity, which is quantified, leads to a slight decrease of the interparticle mesoporosity noticed at 1050
°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.