Carbonization and activation of sol–gel derived carbon xerogels

• Published in: Carbon (New York) Vol. 38; no. 6; pp. 849 - 861
• Main Authors: Lin, Chuan, Ritter, James A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2000; Elsevier Science
• Subjects: A. Carbon xerogels, Resins; B. Carbonization, Activation; Chemistry; Colloidal state and disperse state; D. Porosity; Exact sciences and technology; General and physical chemistry; Porous materials; A. Carbon xerogels, Resins; B. Carbonization, Activation; D. Porosity; Carbonization; Transmission electron microscopy; Sol gel process; Pore structure; Carbon dioxide; Activation; Xerogel; Carbon
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/S0008-6223(99)00189-X

The effects of the carbonization temperature (in N 2) and CO 2-activation time (in 5% CO 2 in N 2) on the pore structure of carbon xerogels, derived from the sol–gel polymerization of resorcinol–formaldehyde resins, were studied in detail. As the carbonization temperature increased, the number of micropores in the 0.6 nm range decreased, with essentially no effect on the pores in the mesopore range, and the cumulative surface areas and pore volumes both decreased, but only marginally. As the CO 2-activation time increased, the number of micropores and mesopores both increased, where pores in the 0.6 nm range eventually became pores in the 0.13 nm range, and the cumulative surface areas and pore volumes both increased significantly. The skeletal densities also increased significantly, approaching that of graphite, with an increase in both the carbonization temperature and CO 2-activation time, but the nanoparticle size was largely unaffected. Weight loss was nearly independent of the carbonization temperature at about 50%, but it was strongly dependent on the CO 2-activation time with a maximum weight loss of about 75%.