Oxidative dehydrogenation of isobutane on carbon xerogel catalysts

The oxidative dehydrogenation of isobutane was investigated with oxidised and nitrogen-doped carbon xerogel catalysts in a fixed-bed reactor at 375 degrees C using a stoichiometric feed composition. The oxygen groups were selectively removed from the surface by thermal treatments performed on the oxidised samples, confirming the carbonyl-quinone groups as the active sites for the reaction, but also highlighting the negative role played by the carboxylic anhydride groups. Turn-over frequencies could be calculated from correlations between the catalytic activity and the concentration of carbonyl-quinone groups. On the other hand, the results obtained with the nitrogen-doped samples showed that the catalytic activity increased with the nitrogen content of the carbon xerogels. (C) 2014 Elsevier By. All rights reserved.