Hydrogen adsorption on functionalized nanoporous activated carbons

X.B. Zhao, B. Xiao, A.J. Fletcher, K.M. Thomas

Research output: Contribution to journalArticle

177 Citations (Scopus)

Abstract

There is considerable interest in hydrogen adsorption on carbon nanotubes and porous carbons as a method of storage for transport and related energy applications. This investigation has involved a systematic investigation of the role of functional groups and porous structure characteristics in determining the hydrogen adsorption characteristics of porous carbons. Suites of carbons were prepared with a wide range of nitrogen and oxygen contents and types of functional groups to investigate their effect on hydrogen adsorption. The porous structures of the carbons were characterized by nitrogen (77 K) and carbon dioxide (273 K) adsorption methods. Hydrogen adsorption isotherms were studied at 77 K and pressure up to 100 kPa. All the isotherms were Type I in the IUPAC classification scheme. Hydrogen isobars indicated that the adsorption of hydrogen is very temperature dependent with little or no hydrogen adsorption above 195 K. The isosteric enthalpies of adsorption at zero surface coverage were obtained using a virial equation, while the values at various surface coverages were obtained from the van't Hoff isochore. The values were in the range 3.9-5.2 kJ mol(-1) for the carbons studied. The thermodynamics of the adsorption process are discussed in relation to temperature limitations for hydrogen storage applications. The maximum amounts of hydrogen adsorbed correlated with the micropore volume obtained from extrapolation of the Dubinin-Radushkevich equation for carbon dioxide adsorption. Functional groups have a small detrimental effect on hydrogen adsorption, and this is related to decreased adsorbate-adsorbent and increased adsorbate-adsorbate interactions.
LanguageEnglish
Pages8880-8888
Number of pages8
JournalJournal of Physical Chemistry B
Volume109
Issue number18
DOIs
Publication statusPublished - May 2005

Fingerprint

activated carbon
Activated carbon
Hydrogen
Adsorption
adsorption
hydrogen
Carbon
Adsorbates
Functional groups
carbon
Carbon Dioxide
Carbon dioxide
Isochores
Nitrogen
carbon dioxide
Carbon Nanotubes
nitrogen
Hydrogen storage
isobars
Extrapolation

Keywords

  • hydrogen adsorption
  • nanoporous activated carbons
  • carbons
  • chemical engineering

Cite this

Zhao, X.B. ; Xiao, B. ; Fletcher, A.J. ; Thomas, K.M. / Hydrogen adsorption on functionalized nanoporous activated carbons. In: Journal of Physical Chemistry B. 2005 ; Vol. 109, No. 18. pp. 8880-8888.
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Hydrogen adsorption on functionalized nanoporous activated carbons. / Zhao, X.B.; Xiao, B.; Fletcher, A.J.; Thomas, K.M.

In: Journal of Physical Chemistry B, Vol. 109, No. 18, 05.2005, p. 8880-8888.

Research output: Contribution to journalArticle

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