| AVS 65th International Symposium & Exhibition | |
| Surface Science Division | Tuesday Sessions |
| Session SS+HC+NS+PS-TuM |
| Session: | Controlling Mechanisms of Surface Chemical Reactions |
| Presenter: | Yosuke Kikuchi, The University of Electro-Communications (UEC-Tokyo), Japan |
| Authors: | Y.K. Kikuchi, The University of Electro-Communications (UEC-Tokyo), Japan J.N. Nakamura, The University of Electro-Communications (UEC-Tokyo), Japan |
| Correspondent: | Click to Email |
It has been reported that nitrogen-doped graphene exhibits high oxygen reduction reaction (ORR) activity, while pristine graphene does not [1]. This is because that doped-nitrogen atoms provide extra electrons to graphene, leading to the stabilization of the reaction intermediates on graphene surface. On the other hand, if curvature can be given to graphene, the chemical bond nature between carbon atoms varies from pure sp2 to sp3-like sp2, and then the reactivity of graphene surface is expected to increase. In this study, we evaluated the ORR activity of fullerene as an example of carbon materials with a curvature.
We investigated the ORR activity of fullerene (C60) using first-principles calculations based on the density functional theory. Electrocatalytic activities were evaluated on the basis of the computational hydrogen electrode model proposed by Nørskov et al. [3] We evaluated the energetics of reaction intermediates in terms of free energy of adsorption. In general, the ORR mainly proceeds in two pathways: For the two-electron pathway (2e−), oxygen molecule (O2) is reduced to hydrogen peroxide (H2O2), and for the direct four-electron pathway (4e−), the final product is water (H2O). H2O2 for the 2e− pathway might corrode a carbon-based electrocatalyst material itself, causing to low durability. Therefore, we also played up the selectivity for the 4e− pathway.
It was found that the fullerene molecule has ORR activity with extremely high selectivity for the four-electron pathway, even if the nitrogen atom is not doped. On the other hand, nitrogen-doped fullerene hardly shows the ORR activity, because the reaction intermediates are overstabilized by nitrogen-doping to fullerene; the maximum electrode potentials show negative values for both the direct four-electron and two-electron pathways.
[1] K. R. Lee, K. U. Lee, J. W. Lee, B. T. Ahn, S. I. Woo, Electrochem. Commun. 12, 1052 (2010)
[2] S. Ni, Z. Li, J. Yang, Nanoscale, 4, 1184 (2012)
[3] J. K. Nørskov, J. Rossmeisl, A. Logadottir, L. Lindqvist, J. Phys. Chem. B 108, 17886 (2004)