Oxidative dehydrogenation of isobutane on carbon xerogel catalysts

• Modified carbon xerogels as catalysts for the oxidative dehydrogenation of isobutane.
• Carbonyl-quinone groups confirmed as the active sites for the reaction.
• The presence of carboxylic anhydride groups decreases the catalytic activity.
• The catalytic activity increases with the nitrogen content of the carbon xerogels.

The oxidative dehydrogenation of isobutane was investigated with oxidised and nitrogen-doped carbon xerogel catalysts in a fixed-bed reactor at 375 °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.

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