[7a-C16-1~12] 17.2 Graphene

[7a-C16-7] Catalytic activity for oxygen reduction reaction on N-doped graphene nanoclusters: Dependence on nitrogen configuration

〇(D)haruyuki matsuyama^1,2, Akira Akaishi^1,2, Jun Nakamura^1,2 (1.UEC-Tokyo, 2.JST-CREST)

Keywords:catalyst, fuel cell, first-principles calculations

We investigated the oxygen reduction reaction (ORR) activity for the hexagonal nitrogen-doped graphene nanoclusters using first-principles calculations within the density functional theory. We consider the N atoms not only just at the edge, but in the vicinity of the edge. The maximum potential for the four-electron (4e^-) pathway of the ORR is higher than that for the two-electron (2e^-) pathway in almost all reaction sites. It is noted that the high selectivity for the 4e^- pathway is assured not just at the edge but inside the cluster. We can recognize the variance of the maximum potentials at each reaction site near the edge but at the deeper site the maximum potential for the 4e^- and 2e^- pathways are distinctly decoupled. It is suggested that the stable reaction is more likely to be achieved at the deeper doping site of the cluster, resulting in the stable operation of the fuel cell. Further, we will discuss effects of the interaction between N atoms on the ORR activity.