II International Symposium on Carbon for Catalysis ABSTRACTS

Our analysis of the chemical activity of the
structural building blocks is supported by
subsequent calculations, which show that the
motifs are able to dissociate oxygen. This
leads to the formation of functional C-O
groups in agreement with the XPSmeasurements
of active OLC-materials [5].
The carbonyl group (indicated by C=O in
Fig. 1) appears among these C-O groups to be
the most promising candidate as an active site
for ODH of ethylbenzene.
OP-I-17
FIG. 1. The approach of an ethylbenzene
molecule (EB) towards functional groups
at an oxidized motif. The ether group is
indicated by C-O-C and the carbonyl
group by C=O.
We finally propose a reaction mechanism, where the dehydrogenation proceeds by
transferring the hydrogen atoms from the ethylbenzene to the carbonyl groups at oxidized
motifs as indicated in Fig. 1. The heat of reaction for the dehydrogenation step at the carbonyl
groups is found to be slightly endothermic in agreement with the elevated temperatures
needed to run the reaction [1].
References
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[5] N. Keller et al., Angew. Chem. Int. Ed. 41, 1885 (2002).
[6] M. F. R. Pereira et al., Carbon 42, 2807 (2004).
[7] M. S. Kane et al., Ind. Eng. Chem. Res. 35, 3319 (1996).
[8] J. M. Carlsson and M. Scheffler, Submitted to Phys. Rev. Lett.
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