Electron energy-loss spectroscopy study of oxygen chemisorption and initial oxidation of Fe(110) |
| |
| Affiliation: | 1. School of Computational Science and Electronics, Hunan Institute of Engineering, Xiangtan 411104, PR China;2. School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, PR China;3. Henan Provincial Key Laboratory for Metal Fuel Battery, Foguang Power Generation Co. Ltd, 50 Holly Street, Zhengzhou 450001, PR China;4. School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, PR China;1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China;2. National Energy Center for Coal to Liquids, Synfuels China Co., Ltd, Huairou District, Beijing 101407, China;1. School of Physics, Northwest University, Xi’an 710127, China;2. School of Chemistry and Physics and QUT Centre for Materials Science, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia |
| |
| Abstract: | The initial stages of the interaction of oxygen with an Fe(110) surface have been studied at 300 K by electron energy-loss spectroscopy with in-situ combined low energy electron diffraction, Auger electron spectroscopy and work-function change measurement. From all the results, four different stages of the oxygen interaction are distinguished: (I) a first dissociative chemisorption up to 3 L, characterized by the c(2×2)-O structure, (II) a second dissociative chemisorption between 3 and 7 L, characterized by the c(3×1)-O structure, (III) incorporation of O adatoms into the selvage between 7 and 30 L, and (IV) oxidation above 30 L leading to the formation of FeO(111), characterized by the diffuse hexagonal diffraction pattern. The sticking probability was found to be initially near unity and fall off rapidly to a minimum value of ≈0.05 at ≈1 L. Particular emphasis was placed upon the investigation of the change in surface electronic properties from those characteristic of them metal to those of the oxide. In stage (I) an energy-loss peak, being attributed to the transition from the 2p orbital of the chemisorbed oxygen, was observed at 6.0 eV, while in stage (II) two additional peaks of the same origin appeared at 7.5 and 9.3 eV due to the formation of the O 2p band. The energy-loss spectrum in the oxide phase was characterized by the peaks at 4.8 and 7.5 eV due to the O2− 2p → Fe2+3d charge-transfer transitions and by a peak at 2.4 eV due to the ligand-field d → d transitions of an Fe2+ ion in FeO. It is shown that the Fe 3dyz,zx and 4sp electrons play a major role in the chemisorption bond (O adatoms located in the long-bridge site), and that for the incorporation process the Fe 3dy2 electrons are also involved in bonding by the symmetry breaking. The change in the Fe 3p-excitation spectrum during oxidation was also investigated. The differences between the experimental results on Fe(100) and (110) surfaces are summarized. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
