Hydration and reduction of molecular beam epitaxy grown VO[subscript x]/a-Fe[subscript 2]O[subscript 3] (0001): Ambient pressure study
Supported vanadium oxides processed under ambient environments have been studied by using X-ray standing wave (XSW) analysis of X-ray fluorescence spectroscopy and X-ray photoelectron spectroscopy (XPS). For the VO{sub x}/{alpha}-Fe{sub 2}O{sub 3}(0001) system, hydration and hydrogen annealing have been carried out under ambient pressure. Vanadium in the hydrated oxide phase occupies two high-symmetry surface adsorption sites with distinct adsorption heights, which resembles the adsorption geometry of fully oxidized vanadium. Reduction by the hydrogen annealing enhanced the V overlayer ordering by relocating a portion of the disordered V to high-symmetry sites. The V atoms located closer to the substrate oxygen layer in the hydrated phase moved toward the substrate after hydrogen reduction, while the V in the higher adsorption site stayed at the same height. The different responses of two adsorption sites to the reduction process are discussed and related to activities of the two sites.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1005465
- Journal Information:
- J. Phys. Chem. C, Vol. 113, Issue (4) ; 01, 2009; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- ENGLISH
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