N, O Co-Doped Graphene as a Potential Catalyst for the Oxygen Reduction Reaction

The detailed oxygen reduction reaction (ORR) pathways on N, O co-doped graphene are investigated, and the catalytic activity is predicted by density functional theory (DFT) transition-state calculations. Our first-principles calculation results show that the O-2 molecule is chemisorbed on the carbon adjacent to nitrogen atom, and prefer hydrogenation into OOH species rather than direct breakage of the O-O bond. It is predicted that the O-2 is inherently favorable for reduction into H2O on N, O co-doped graphene following a direct 4e(-) pathway. Besides, the adsorption energies of the ORR species and the activation energies of the ORR steps on N, O co-doped graphene are all close to those of Pt(111), which indicates a Pt-like catalytic activity. It is demonstrated that the high ORR activity could be attributed to the oxygen-induced charge delocalization, leading to an increase of the adsorption energy of the ORR species. Consequently, our theoretical prediction suggests that nonprecious N, O co-doped graphenes could possess catalytic activity for ORR comparable to that of precious Pt catalysts. (C) 2019 The Electrochemical Society.