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Tight-Binding Quantum Chemical Molecular Dynamics of Oxygen Migration of Rh-supporting CeO2 Surfaces

Published online by Cambridge University Press:  19 August 2014

Ai Suzuki ,
Ryuji Miura ,
Nozomu Hatakeyama  and
Akira Miyamoto
Ai Suzuki
Affiliation:
New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, 980-8579, Japan
Ryuji Miura
Affiliation:
New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, 980-8579, Japan
Nozomu Hatakeyama
Affiliation:
New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, 980-8579, Japan
Akira Miyamoto
Affiliation:
New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, 980-8579, Japan
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Abstract

The electronic properties of the interface between Rh clusters and CeO2 (111), (110) and (100) surfaces were studied using an isothermal-isobaric (NPT) ensemble at 773 K and 101.343 kPa using the tight binding-quantum chemical molecular dynamics (TB-QCMD) method. The amount of electronic exchange by interaction at the interface between the supported Rh55 clusters and each CeO2 surface was investigated quantitatively. A comparison of the mean square displacement (MSD) showed that the topmost oxygens on the Rh-supporting CeO2 surface exhibited higher mobility than those of the bare CeO2 surface. Although the mobility of the topmost oxygens on the bare CeO2 surface was in the order (100) > (110) > (111), this sequence was altered by the presence of Rh, so that the oxygen mobility for the more open (110) surface was the largest. The amount of electron exchange that occurred between Rh and the CeO2 (110) surface was also larger than for the (111) or (100) surface. The Ce 4f orbitals on the CeO2 (110) surface exhibited the strongest mixing with Rh 4d orbitals, which simultaneously caused restructuring and instability of the topmost Ce-O bonds. This enhancement of oxygen migration in the presence of Rh was occurred together with an increase in the number of oxygen vacancies on the ceria surface. This was because the topmost oxygens was shifted to have a stronger affinity with Rh and thus formed stronger bonds with Rh than with Ce.

Keywords

Rhsurface chemistrysurface reaction
Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 1704: Symposium QQ – Computationally Enabled Discoveries in Synthesis, Structure and Properties of Nanoscale Materials , 2014 , mrss14-1704-qq07-04
Copyright
Copyright © Materials Research Society 2014 

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References

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