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Several di ff erent charge transfer and Ce 3 + localization scenarios for Rh – CeO 2 ( 111 )
| Content Provider | Semantic Scholar |
|---|---|
| Author | Lu, Zhansheng Yang, Zong-Xian Hermansson, Kersti Castleton, C. W. M. |
| Abstract | We present DFT+U based electronic structure calculations in a p(3 3) slab supercell, for low coverages of atomically dispersed Rh interactingwith the CeO2(111) surface, comparing Rh as an adatom, and as a dopant substituted into the surface layer. We find that, energetically, a Rh atom approaching a ceria(111) surface with both sparse O and Ce vacancies present strongly prefers to heal the Ce vacancies, but next it prefers to adsorb on a stoichiometric region rather than healing an O vacancy. In the adatom system, Rh is oxidized by electron transfer to a 4f orbital on one Ce ion in the surface layer, which is then nominally converted from Ce / Ce (i.e. Rh adatoms are single donors). We show that there are a number of different local minima, with Ce localization at 1, 2 or 3 nearest neighbour Ce sites. The second neighbour is the most stable, but all are close in energy. In the Rh-doped system (Rh replaces Ce), Rh is oxidized by charge transfer to neighbouring O atoms, and Rh doping leads to deep acceptor and donor states. Rh is not stable in the O sublattice. Moreover, based on vacancy formation energies, we find that oxygen vacancy formation is strongly enhanced in the vicinity of Rh dopants, but slightly suppressed in the vicinity of Rh adatoms. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://irep.ntu.ac.uk/id/eprint/27338/1/PubSub5141_Castleton.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
