New Insights into the Structure of Nanoporous Carbons from NMR, Raman, and Pair Distribution Function Analysis

Research output: Contribution to journalArticlepeer-review

Authors

  • Alexander C. Forse
  • Céline Merlet
  • Elizabeth K. Humphreys
  • John M. Griffin
  • Mesut Aslan
  • Marco Zeiger
  • Volker Presser
  • Yury Gogotsi
  • Clare P. Grey

Colleges, School and Institutes

Abstract

The structural characterization of nanoporous carbons is a challenging task as they generally lack long-range order and can exhibit diverse local structures. Such characterization represents an important step toward understanding and improving the properties and functionality of porous carbons, yet few experimental techniques have been developed for this purpose. Here we demonstrate the application of nuclear magnetic resonance (NMR) spectroscopy and pair distribution function (PDF) analysis as new tools to probe the local structures of porous carbons, alongside more conventional Raman spectroscopy. Together, the PDFs and the Raman spectra allow the local chemical bonding to be probed, with the bonding becoming more ordered for carbide-derived carbons (CDCs) synthesized at higher temperatures. The ring currents induced in the NMR experiment (and thus the observed NMR chemical shifts for adsorbed species) are strongly dependent on the size of the aromatic carbon domains. We exploit this property and use computer simulations to show that the carbon domain size increases with the temperature used in the carbon synthesis. The techniques developed here are applicable to a wide range of porous carbons and offer new insights into the structures of CDCs (conventional and vacuum-annealed) and coconut shell-derived activated carbons.

Details

Original languageEnglish
Pages (from-to)6848-6857
Number of pages10
JournalChemistry of Materials
Volume27
Issue number19
Early online date25 Sep 2015
Publication statusPublished - 2 Oct 2015