Oxidative dehydrogenation of isobutane on phosphorous-modified graphitic mesoporous carbon

Graphitic mesoporous carbon was modified with phosphorous heteroatoms in order to tune the catalytic selectivity and to investigate the roles of different oxygen species for the oxidative dehydrogenation reaction of isobutane to isobutene. Small changes in the isobutane apparent activation energy are consistent with the notion that the phosphorous groups do not change the nature of the active sites but they interfere with the availability of the sites. Our results show that the improvement on selectivity is not proportional to the amount of phosphorous added. Small phosphorous content improved the selectivity by suppressing the combustion of isobutane. However, a higher amount of phosphorous groups lead to coverage of selective quinone sites and/or creation of active sites favorable to total oxidation.

Graphitic mesoporous carbon was modified with phosphorous heteroatoms in order to tune the catalytic selectivity for the oxidative dehydrogenation reaction of isobutane to isobutene. Our results indicate that there is an optimum amount of phosphorous groups that should be added so that only unselective sites are blocked.Figure optionsDownload as PowerPoint slideResearch highlights
► Graphitic mesoporous carbons with open fullerene-like cavities promotes the selective oxidative dehydrogenation reaction of isobutane to isobutene.
► Small amounts of phosphorous heteroatom drives the reaction to higher selectivities as it inhibits formation of COx products.
► Phosphorous groups do not change the nature of the active sites but they interfere with the availability of the sites.
► Optimum amount of phosphorous groups should be added so that only unselective sites are blocked.