Imaging the structure and porosity of active carbons by scanning tunneling microscopy

J. I. Paredes, A. Martínez-Alonso, P. X. Hou, T. Kyotani, J. M.D. Tascón

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Scanning tunneling microscopy (STM) has been employed for a comparative structural characterization, down to the atomic scale, of a representative set of porous carbons with different adsorption characteristics and prepared either by activation (physical or chemical) or templating techniques. The studied materials included a chemically activated, supermicroporous high surface area carbon, two activated carbons containing both micro- and mesopores synthesized by physical activation, an ultramicroporous carbon molecular sieve, and an ordered microporous carbon templated in the nanochannels of zeolite Y. In general, good agreement was found between the porous structures as imaged by STM and the porous texture derived from gas adsorption data for all the carbons investigated. The activated carbon samples were dominated by networks of slit type micropores and, in some cases, by mesopores of varied morphologies. By contrast, the zeolite-templated carbon exhibited rounded micropore morphology, and the carbon molecular sieve displayed a rather featureless conformation dominated by voids only below 1 nm wide. The structural differences observed by STM were interpreted in terms of the different preparation procedures of the studied carbons. In particular, the templated carbon consisted of minute clusters about 1 nm in diameter that were interpreted to be formed within the extremely confined, microporous spaces of the zeolite Y template.

Original languageEnglish
Pages (from-to)2469-2478
Number of pages10
JournalCarbon
Volume44
Issue number12
DOIs
Publication statusPublished - 2006 Oct

Keywords

  • Adsorption
  • Porosity
  • Porous carbon
  • Scanning tunneling microscopy

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

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