Periodical
Formation of a Rhodium Surface Oxide Film in Rhn/CeO2(111) Relevant for Catalytic CO Oxidation: A Computational Study
| العنوان: | Formation of a Rhodium Surface Oxide Film in Rhn/CeO2(111) Relevant for Catalytic CO Oxidation: A Computational Study |
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| المؤلفون: | Song, Weiyu, Popa, Cristina, Jansen, Antonius P. J., Hensen, Emiel J. M. |
| المصدر: | The Journal of Physical Chemistry - Part C; November 2012, Vol. 116 Issue: 43 p22904-22915, 12p |
| مستخلص: | The structure of small Rhn(n= 1–10) clusters and corresponding Rh-oxide (RhnOm) clusters (n= 1–4; m= 1–9) supported on a stoichiometric CeO2(111) surface has been investigated using density functional theory corrected for on-site Coulombic interactions (DFT+U) with the goal to identify a realistic model for Rh/CeO2-based CO oxidation catalysts. Rhnclusters on ceria prefer to adopt a three-dimensional morphology. The adsorption of oxygen leads to the reconstruction of such clusters into a two-dimensional Rh-oxide film. The stability of RhnOmspecies is determined by evaluating the reaction energy for the stepwise oxidation of Rhn, which is to be compared with data for the experimental fresh catalysts. It is found that with increasing cluster size the surface oxide phase becomes increasingly stable against the isolated RhO3form under oxidative conditions. The Helmholtz free energy change for RhnOmclusters with varying mwas determined for the reduction by CO and oxidation by O2. In this way, it was found that Rh-oxide species are more stable than the corresponding pure Rh clusters when supported on CeO2(111). This suggests that the active site for CO oxidation is a Rh surface-oxide. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 19327447 19327455 |
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| DOI: | 10.1021/jp306863d |