Oxidative dehydrogenation of ethylbenzene to styrene over ultra-dispersed diamond and onion-like carbon

• Published in: Carbon (New York) Vol. 45; no. 11; pp. 2145 - 2151
• Main Authors: Su, Dangsheng, Maksimova, Nadezhda I., Mestl, Gerhard, Kuznetsov, Vladimir L., Keller, Valérie, Schlögl, Robert, Keller, Nicolas
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2007
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2007.07.005

The catalytic properties of sp
3-hybridized ultra-dispersed diamond and sp
2-hybridized onion-like carbon in the oxidative dehydrogenation of ethylbenzene to styrene were investigated, highlighting the structure sensitivity of the reaction. The sp
3-carbon led initially to C–C cleavage and benzene formation, while a switchover of the main reaction pathway into the styrene formation occurred with time on stream due to the formation of surface sp
2 carbon, required for the selective styrene formation. This was confirmed by the behavior and the high stable styrene selectivity shown by onion-like carbons. High temperature oxygen pre-treatment created catalytically active species at the sp
2 carbon surface, confirming that a high thermal stability carbon–oxygen complex was the active surface site for forming styrene.