| AVS 57th International Symposium & Exhibition | |
| Graphene Focus Topic | Monday Sessions |
| Session GR+NS-MoA |
| Session: | Graphene: Chemical Reactions |
| Presenter: | J. Nakamura, University of Tsukuba, Japan |
| Authors: | J. Nakamura, University of Tsukuba, Japan T. Kondo, University of Tsukuba, Japan J. Oh, University of Tsukuba, Japan D. Guo, University of Tsukuba, Japan Y. Honma, University of Tsukuba, Japan T. Machida, University of Tsukuba, Japan |
| Correspondent: | Click to Email |
Understanding the interface interaction between metal nano-clusters and carbon supports composed of graphite materials is one of the most important needs in the development of carbon related-catalysts. We have studied the carbon support effects on the electrocatalysts for fuel cell as well as the interface interaction using model catalysts of Pt-deposited highly oriented pyrolytic graphite (HOPG) by IETS-STS-STM, TPD, and molecular/atomic beam technique. Here, we report the formation of non-bonding state in the vicinity of defects on the HOPG surface. We have measured STS spectra at many different points in the vicinity of the point defect. STS spectra were very different depending on the point of the measurement. In the directions perpendicular to short zigzag edges at the point defect, STS peaks appear near the Fermi level, suggesting the edge state or non-bonding state. The non-bonding state propagates 3-4 nanometers away from the defect with three-fold symmetry. No such a STS peak was observed near the point defect in the other directions. We thus constructed a STS map showing the distribution of the non-bonding state. We also observed spatial “oscillations” in the dI/dV peak position and the intensity. The oscillations have been explained as electron-electron interaction or electron-hole interaction. We currently consider that the non-bonding state is responsible for the chemical reactivity such as adsorption of atom, molecules, and clusters.
References
1. E. Yoo, J. Nakamura, et al., Nano Letters 9 (2009) 2255.
2. T. Kondo, J. Nakamura, et al., Phys. Rev. B 80 (2009) 233408.
3. J. Oh, T. Kondo, J. Nakamura, et al., J. Phys. Chem. Lett. 1 (2010) 463.
4. T. Kondo, J. Nakamura, et al.,J. Phys. Chem. C 112 (2008) 15607.