On the Thermal Stability of Aryl Groups Chemisorbed on Graphite

Hans Van Gorp, Peter Walke, Joan Teyssandier, Brandon E. Hirsch, Hiroshi Uji-I, Kazukuni Tahara, Yoshito Tobe, Mark Van Der Auweraer, Steven De Feyter

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Abstract

The covalent functionalization of carbon-based materials through aryldiazonium chemistry has emerged as a powerful tool for physicochemical property modification. However, the characterization techniques traditionally used to assess the stability of any modification, such as thermogravimetric analysis (TGA), do not allow covalent detachment to be discriminated from the loss of physisorbed material. Here, we present a general method to differentiate these two processes by combining scanning probe microscopy with Raman spectroscopy. Using covalently modified highly oriented pyrolytic graphite (HOPG), we show that the thermally induced covalent bond breaking between the aryl groups and the HOPG surface can be directly monitored through this combined approach. Moreover, temperature-dependent Raman spectroscopy allows the kinetics of this bond breaking to be studied. Desorption activation energies can thus be initially estimated for aryl groups bearing different substituents. Finally, we highlight that the pristine HOPG structure can be restored at a relatively low temperature, opening the way for reversible covalent modification. Our results alight on a general methodology for the full characterization of covalently modified carbon materials.

Original languageEnglish
Pages (from-to)1980-1990
Number of pages11
JournalJournal of Physical Chemistry C
Volume124
Issue number3
DOIs
Publication statusPublished - 23 Jan 2020

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Van Gorp, H., Walke, P., Teyssandier, J., Hirsch, B. E., Uji-I, H., Tahara, K., Tobe, Y., Van Der Auweraer, M., & De Feyter, S. (2020). On the Thermal Stability of Aryl Groups Chemisorbed on Graphite. Journal of Physical Chemistry C, 124(3), 1980-1990. https://doi.org/10.1021/acs.jpcc.9b09808