Microporosity in carbon aerogels

• Published in: Journal of non-crystalline solids Vol. 225; no. 1-3; pp. 210 - 214
• Main Authors: Reichenauer, G, Emmerling, A, Fricke, J, Pekala, R.W
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-04-1998; Elsevier
• Subjects: Carbon aerogels; Chemistry; CO 2 adsorption; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Microporosity; Small angle X-ray scattering (SAXS); A120; C320; Microporosity; Small angle X-ray scattering (SAXS); P300; CO 2 adsorption; Carbon aerogels; S470; Pyrolysis; Adsorption; Aerogel; Carbon dioxide; Small angle X ray scattering; Experimental study; Carbon; Formaldehyde; Resorcinol
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/S0022-3093(98)00118-5

Carbon aerogels prepared via pyrolysis of resorcinol-formaldehyde gels (R/C 200) were investigated with respect to porosity on a length scale below 2 nm. Microporosity as a function of sample density (120–620 kg/m
3) and pyrolysis temperature (1050–2100°C) were studied by CO
2 adsorption at 273 K and small angle X-ray scattering (SAXS). Micropore size and volume deduced from SAXS data are almost independent of bulk density, while adsorption of CO
2 is significantly smaller for higher aerogel densities. Upon increase of pyrolysis temperature from 1050°C to 2100°C a drastic enlargement of the structures on all length scales is observed by SAXS. Simultaneously, the micropore volume accessible to CO
2 almost vanishes, indicating the evolution of `closed' micropores.