Ab initio studies of propane dehydrogenation to propene with graphene

First principles calculations are employed to study the dehydrogenation of propane to propene using graphene. The interrelationship between the thermodynamic stability, the catalytic activity and the intrinsic capacity for hydrogen abstraction is employed to identify active graphene nanosheets. The atomistic nature of propyl species anchor sites in active graphene ribbons is clarified as a partially delocalised radical formed on one orbital, and not a typical dangling bond defect state associated with an open-volume defect. Redistribution of charges into zones of accretion and depletion, in the vicinity of the adsorption site, suggests that the delocalisation of the active site at finite temperatures is a distinct possibility that cannot be overruled. Since the active graphene models are obtained from geometrical variants of locally reconstructed carbon divacancies, results of this study suggest that the large-scale synthesis of narrow strips is the key step in the rational design of graphene-based active catalysts instead of large-area sheets.