Paper SS-MoA1
Controlling Surface Reactivity of an Ultrathin MgO Film by Interface Tuning
Monday, October 28, 2013, 2:00 pm, Room 201 A
| Session: |
Metal Oxides: Reactivity and Catalysis |
| Presenter: |
Y. Kim, RIKEN, Japan |
| Authors: |
Y. Kim, RIKEN, Japan
J. Jung, RIKEN, Japan
H.-J. Shin, UNIST, Republic of Korea
M. Kawai, University of Tokyo, Japan
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| Correspondent: |
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Ultrathin oxide films grown on metal substrates have been a subject of great interest not only as a supporting material for chemically active nanoparticles but also as a catalyst in the field of heterogeneous catalysis. We have demonstrated that the chemical reactivity for water dissociation on an ultrathin MgO film supported by the Ag(100) substrate depends greatly on film thickness and be enhanced compared to that achieved with their bulk counterpart using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations [1]. The change of chemical reactivity of ultrathin MgO film depending on the film thickness can be explained by the strengthening of the interaction between the oxide and metal interface layers [2]. This result implies that the artificial manipulation of the local structure at the oxide-metal interface is expected to play a pivotal role in controlling the catalytic activity of oxide film. We have also examined and compared the water dissociation on various model systems with defects at the oxide-metal interface of the 2-ML MgO/Ag(100) using periodic DFT calculations [2]. Our results clearly show that such structural imperfections at the interface can improve the chemical reactivity of the MgO film supported by an Ag substrate. This is closely correlated with the accompanied change of charge distribution of the oxide surface due to the accumulation of transferred charge density at the interface. In addition, the chemical reactions on the ultrathin oxide film surface can be tuned by interface defects regardless of the charging of adsorbates. A recent result of coupling between molecular vibration and surface phonon in the CO hopping process on MgO/Ag(100) with tunneling electrons will also be introduced [3].
[1] H.-J. Shin, J. Jung, K. Motobayashi, S. Yanagisawa, Y. Morikawa, Y. Kim, and M. Kawai, Nat. Mater. 9, 442 (2010).
[2] J. Jung, H.-J. Shin, Y. Kim, and M. Kawai, Phys. Rev. B 82, 085413 (2010); J. Am. Chem. Soc. 133, 6142 (2011); J. Am. Chem. Soc. 134, 10554 (2012).
[3] H.-J. Shin, J. Jung, M. Kawai, and Y. Kim, submitted.