Journal article

Monolithic resorcinol–formaldehyde alcogels and their corresponding nitrogen-doped activated carbons

  • Civioc, Romain Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland
  • Lattuada, Marco Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
  • Koebel, Matthias M. Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland
  • Galmarini, Sandra Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland
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    17.04.2020
Published in:
  • Journal of Sol-Gel Science and Technology. - 2020, vol. 95, no. 3, p. 719–732
English Here we report the adaptation of formaldehyde crosslinked phenolic resin-based aerogel and xerogel synthesis to ethanol-based solvent systems. Three specific formulations, namely one resorcinol–formaldehyde (RF) and two resorcinol– melamine–formaldehyde (RMF) systems were studied. As-prepared resins were characterized in terms of envelope and skeletal density. Furthermore, resin samples were pyrolyzed and activated in a CO2 gas atmosphere using a single-step protocol. The corresponding carbon materials featured high surface areas, moderate water uptake capacity and thermal conductivities in the 0.1 W.m−1K−1 range, in line with comparable activated carbons. The amount of formaldehyde in the synthesis of the RMF derived carbons proved to be a critical parameter in terms of both structural features and amount of N dopant in the carbonaceous matrix. Furthermore, a high formaldehyde concentration also has a drastic effect on the pore structure of the corresponding RMF carbons, leading primarily to mesopore formation without almost any macropore formation. Perhaps more importantly, the effect of the ammonia curing catalyst concentration on the material microstructure showed the opposite effect as observed in classical, water-based phenolic resin preparations. The ethanol-based synthesis clearly affects the pore structure of the resulting materials but also opens up the possibility to create inorganic/organic hybrid materials by simple combination with classical alkoxide-based silica sol–gel chemistry.
Faculty
Faculté des sciences et de médecine
Department
Département de Chimie
Language
  • English
Classification
Chemistry
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/308756
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