Carbon nanotubes : innovative heterogeneous gas phase catalysts Since the coke deposition on the inorganic oxide in the course of ODEB to styrene has been considered as the true catalytically active substance various carbonaceous materials have shown to be active and selective catalysts for this reaction. It has been confirmed that oxygenated surface functional groups of catalyst especially carbonyl quinoid and hydroxyl groups are responsible for the catalytic performance. Therefore the focus in this study is in the creation of oxygen containing functional groups on the surface of carbon nanotubes by partial oxidation using high potential oxidizing agents including hydroxyl radicals and ozone in gas phase followed by investigating the influences of these groups on the ODEB catalytic behavior. The effects of the oxidative treatment methods on the textural structural and chemistry surface of MWCNTs as well as comparative investigations on the catalysts before and after the ODEB have been conducted by using a series of analytical techniques including TGA BET surface area Raman spectroscopy TEM FTIR and XPS. It is found that as received MWCNTs possessed a number of oxygenated surface groups as a result of CVD method. Further oxidation treatment with highly active hydroxyl radicals generated via UV H2O2 process increased substantially the formation of oxygenated surface functional groups compared to as received MWCNTs particularly hydroxyl and carbonyl groups. Using hydrogen peroxide solutions with concentrations higher than 35 wt.% for the radical oxidation of MWCNTs did not enhance the surface oxygen content as expected. ...