Oxygen molecule dissociation on carbon nanostructures with different types of nitrogen doping

The energy barrier of oxygen molecule dissociation on carbon nanotubes or graphene with different types of nitrogen doping is investigated using density functional theory. The results show that the energy barriers can be reduced efficiently by all types of nitrogen doping in both carbon nanotubes and graphene. Graphite-like nitrogen and Stone-Wales defect nitrogen decrease the energy barrier more efficiently than pyridine-like nitrogen, and a dissociation barrier lower than 0.2 eV can be obtained. Higher nitrogen concentration reduces the energy barrier much more efficiently for graphite-like nitrogen. These observations are closely related to partial occupation of pi* orbitals and change of work functions. Our results thus provide useful insights into the oxygen reduction reactions.