▎ 摘　　要

Nitrogen-doped graphene represents a good alternative and a promising catalytic structure for the oxygen reduction reaction (ORR) in fuel cell applications compared with the more costly Pt-containing catalyst materials. In the present study, using density functional theory calculations, we analyze the effect of the oxygen functional groups (HO*/O*) that are highly probable to be coadsorbed in the vicinity of reaction sites on the undoped and N-doped zigzag graphene nanoribbon edges. These coadsorbates on some of the structures produce local structural changes around the active sites (i.e., the cyclic C-N bond breaking when O* is adsorbed near the most outside graphitic nitrogen.ending in the formation of the pyridine site and of new C active sites, the formation of hydrogen bonds, etc.) and accordingly an electronic modification of the C active sites compared to the structures without coadsorbates (i.e., variation of the p state intensities close to the Fermi level and accordingly of the bond strength that varies proportionally with the distance from the coadsorbate). All these changes are reflected in the final activities of the sites toward the ORR and results in either higher or lower theoretical overpotentials. These overpotentials were patterned into a volcano plot. The most active sites are those from the locally modified structures-when graphitic N was changed in protonated pyridinic site by the presence of O* coadsorbate, the site next to graphitic N when in the vicinity is the coadsorbed HO* fragment and the edge of undoped graphene with no coadsorbate present. In this last case, the coadsorbate worsens the activity. The study was performed in the context of almost nonexistent studies of this type.coadsorbents effects on graphene systems.