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Structure and catalytic reactivity of Rh oxides

Gustafson, Johan LU ; Westerström, Rasmus LU ; Resta, Andrea LU ; Mikkelsen, Anders LU ; Andersen, Jesper N LU ; Balmes, O.; Torrelles, X.; Schmid, M.; Varga, P. and Hammer, B., et al. (2009) Workshop of the European-Synchrotron-Radiation-Facility, 2009 In Catalysis Today 145(3-4). p.227-235
Abstract
Using a combination of experimental and theoretical techniques, we show that a thin RhO2 surface oxide film forms prior to the bulk Rh2O3 corundum oxide on all close-packed single crystal Rh surfaces. Based on previous reports, we argue that the RhO2 surface oxide also forms on vicinal Rh surfaces as well as on Rh nanoparticles. The detailed structure of this film was previously determined using UHV based techniques and density functional theory. In the present paper, we also examine the structure of the bulk Rh2O3 corundum oxide using surface X-ray diffraction. Being armed with this structural information, we have explored the CO oxidation reaction over Rh(1 1 1), Rh(1 0 0) and Pt25Rh75(1 0 0) at realistic pressures using in situ surface... (More)
Using a combination of experimental and theoretical techniques, we show that a thin RhO2 surface oxide film forms prior to the bulk Rh2O3 corundum oxide on all close-packed single crystal Rh surfaces. Based on previous reports, we argue that the RhO2 surface oxide also forms on vicinal Rh surfaces as well as on Rh nanoparticles. The detailed structure of this film was previously determined using UHV based techniques and density functional theory. In the present paper, we also examine the structure of the bulk Rh2O3 corundum oxide using surface X-ray diffraction. Being armed with this structural information, we have explored the CO oxidation reaction over Rh(1 1 1), Rh(1 0 0) and Pt25Rh75(1 0 0) at realistic pressures using in situ surface X-ray diffraction and online mass spectrometry. In all three cases we find that an increase of the CO2 production coincides with the formation of the thin RhO2 surface oxide film. In the case of Pt25Rh75(1 0 0), our measurements demonstrate that the formation of bulk Rh2O3 corundum oxide poisons the reaction, and argue that this is also valid for all other Rh surfaces. Our study implies that the CO oxidation reaction over Rh surfaces at realistic conditions is insensitive to the exact Rh substrate orientation, but is rather governed by the formation of a specific surface oxide phase. (C) 2008 Elsevier B.V. All rights reserved. (Less)
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Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
surfaces, Single crystal, In situ, Rhodium, Surface X-ray diffraction (SXRD), Surface structure
in
Catalysis Today
volume
145
issue
3-4
pages
227 - 235
publisher
Elsevier
conference name
Workshop of the European-Synchrotron-Radiation-Facility, 2009
external identifiers
  • wos:000269006900007
  • scopus:67650709485
ISSN
0920-5861
DOI
10.1016/j.cattod.2008.11.011
language
English
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yes
id
409127ce-f112-4784-8370-1a2c289fb238 (old id 1477366)
date added to LUP
2009-09-22 15:35:40
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2017-07-02 03:54:34
@inproceedings{409127ce-f112-4784-8370-1a2c289fb238,
  abstract     = {Using a combination of experimental and theoretical techniques, we show that a thin RhO2 surface oxide film forms prior to the bulk Rh2O3 corundum oxide on all close-packed single crystal Rh surfaces. Based on previous reports, we argue that the RhO2 surface oxide also forms on vicinal Rh surfaces as well as on Rh nanoparticles. The detailed structure of this film was previously determined using UHV based techniques and density functional theory. In the present paper, we also examine the structure of the bulk Rh2O3 corundum oxide using surface X-ray diffraction. Being armed with this structural information, we have explored the CO oxidation reaction over Rh(1 1 1), Rh(1 0 0) and Pt25Rh75(1 0 0) at realistic pressures using in situ surface X-ray diffraction and online mass spectrometry. In all three cases we find that an increase of the CO2 production coincides with the formation of the thin RhO2 surface oxide film. In the case of Pt25Rh75(1 0 0), our measurements demonstrate that the formation of bulk Rh2O3 corundum oxide poisons the reaction, and argue that this is also valid for all other Rh surfaces. Our study implies that the CO oxidation reaction over Rh surfaces at realistic conditions is insensitive to the exact Rh substrate orientation, but is rather governed by the formation of a specific surface oxide phase. (C) 2008 Elsevier B.V. All rights reserved.},
  author       = {Gustafson, Johan and Westerström, Rasmus and Resta, Andrea and Mikkelsen, Anders and Andersen, Jesper N and Balmes, O. and Torrelles, X. and Schmid, M. and Varga, P. and Hammer, B. and Kresse, G. and Baddeley, C. J. and Lundgren, Edvin},
  booktitle    = {Catalysis Today},
  issn         = {0920-5861},
  keyword      = {surfaces,Single crystal,In situ,Rhodium,Surface X-ray diffraction (SXRD),Surface structure},
  language     = {eng},
  number       = {3-4},
  pages        = {227--235},
  publisher    = {Elsevier},
  title        = {Structure and catalytic reactivity of Rh oxides},
  url          = {http://dx.doi.org/10.1016/j.cattod.2008.11.011},
  volume       = {145},
  year         = {2009},
}