Enhanced oxygen reduction reactions in fuel cells on H-decorated and B-substituted graphene.

In the light of recent experimental research on the oxygen reduction reaction (ORR) with carbon materials doped with foreign atoms, we study the performance of graphene with different defects on this catalytic reaction. In addition to the reported N-graphene, it is found that H-decorated and B-substituted graphene can also spontaneously promote this chemical reaction. The local high spin density plays the key role, facilitating the adsorption of oxygen and OOH, which is the start of ORR. The source of the high spin density for all of the doped graphene is attributed to unpaired single π electrons. Meanwhile, the newly formed C-H covalent bond introduces a higher barrier to the p electron flow, leading to more localized and higher spin density for H-decorated graphene. At the same time, larger structural distortion should be avoided, which could impair the induced spin density, such as for P-substituted graphene.