Dissociation of O2 molecule on Fe/Nx clusters embedded in C60 fullerene, carbon nanotube and graphene

The O-2 dissociation and yielding two separated O atoms is an essential step for the oxygen reduction reaction. Dissociation of the strong bond in the O-2 often involves large activation barriers on metal particles used as catalysts. Here, the O-2 dissociation on the Fe/N-x clusters embedded in the fullerene C-60, carbon nanotube, and graphene nanomaterials have been studied theoretically using density functional theory. The following outcomes can be derived from our calculations: (1) The Fe/N clusters embedded in the C-60, carbon nanotube, and graphene enhance the reactivity of these nanomaterials, however, it is more effective in the case of Fe/N. clusters embedded in the graphene. (2) Consistent with the prediction of the reactivity descriptors, the maximum catalytic activity toward the O-2 dissociation is related to the Fe/N-4 cluster embedded in graphene. (3) The adsorption energies of the O-2 adsorbed on the Fe/N. clusters embedded in the C-60, carbon nanotube and graphene increase with the increase Fe transition metal positive charges. (4) Our study demonstrates that the Fe/N-4 cluster embedded in graphene can act as driving force for the O-2 dissociation. (5) The energy barrier of the O-2 dissociation process shows that the O-2 dissociation on the Fe/N-4 cluster embedded in the graphene will be kinetically preferable. These predictions open the route for the experimental studies of catalysts that offer high activity for oxygen reduction reaction processes.