First-Principles Study on Nitrobenzene-Doped Graphene as a Metal Free Electrocatalyst for Oxygen Reduction Reaction

The electrocatalyst, nitrobenzene molecular doped graphene, for the oxygen reduction reaction (ORR) is investigated by the first-principles calculations. We find that zigzag edge (Z), doped armchair edge (NBA), and the opposite-side edge of doped zigzag nanoribbon (NBZ-2) are three active centers that contribute to the efficient catalytic performance. Our calculations suggest that such excellent electrocatalytic properties originate from the induced high asymmetry spin density and charge redistribution. The calculated onsite potentials are -0.13, -0.43, and -0.11 V for Z, NBA, and NBZ-2, which are close to the experimental values of -0.20 V on NBG and -0.24 V on graphene. We also find that the electrocatalytic activity and the tolerance of methanol depend on the doped configurations. Therefore, the carefully controllable synthesis is highly expected to further improve the ORR activity of nitrobenzene-doped graphene.