Structure of Stoichiometric and Oxygen-Rich Ultrathin FeO(111) Films Grown on Pd(111)
Monolayer thin FeO(111) films were grown on Pd(111) and oxidized by atomic oxygen (O). The stoichiometric and oxidized films were studied in detail by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Compared to the previously studied FeO(111)/Pt(111) system, small structural differences were observed for stoichiometric FeO monolayer films. Upon O exposure, the stoichiometric FeO film reconstructs, leading to the formation of new O-rich structures incorporating increasing amounts of additional O atoms. At low O exposures, the STM images exhibit bright features of regularly sized triangular structures assigned to O-adatom dislocation loops. A model of this O-rich structure composed of four-fold O-coordinated Fe atoms is proposed and confirmed by DFT calculations. Furthermore, these O dislocation loops induce the inversion of the FeO film and enclose portions of the film in which the order of the high-symmetry domains is inverted. For higher O exposures, the formation of FeO2–x islands coexisting with O-adatom dislocations and stoichiometric FeO patches was observed. Finally, these FeO2–x islands are reminiscent of the O-rich structures previously reported for FeO supported on Pt(111) and are catalytically active toward CO oxidation.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- DOE Office of Science; USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1097932
- Journal Information:
- Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 29 Vol. 117; ISSN 1932-7447
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
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