期刊
TOPICS IN CATALYSIS
卷 57, 期 10-13, 页码 890-898出版社
SPRINGER/PLENUM PUBLISHERS
DOI: 10.1007/s11244-014-0248-x
关键词
FeO; Pt; XPS; Oxide/metal interface; Oxidation; Reduction
资金
- National Natural Science Foundation of China [21222305, 11079005, 20923001]
- Ministry of Science and Technology of China [2011CBA00503, 2013CB933100]
Structural changes of FeOx nanostructures supported on Pt(111) and Pt foil with response to oxidation and reduction treatments in O-2 and H-2 atmospheres upto 1.0 bar have been investigated by using X-ray photoelectron spectroscopy and scanning tunneling microscopy. We show that submonolayer O-Fe bilayer (FeO) structure on Pt(111) can be transformed to O-Fe-O trilayer (FeO2) upon oxidation in 5.0 x 10(-6) mbar O-2, while the FeO to FeO2 transformation happens over the full FeO film only with the O-2 partial pressure above 1.0 x 10(-3) mbar. Reduction of the submonolayer FeO2 structure back to the FeO structure occurs when exposed to 1.0 mbar H-2 at room temperature (RT). In contrast, the full FeO2 structure can be kept even under 1.0 bar H-2 exposure condition. The FeOx coverage and FeOx/Pt boundary play a critical role in the redox behavior of the supported FeOx nanostructures. Furthermore, we show that the FeOx nanostructures supported on Pt foil can be oxidized in a similar way as those on the Pt(111) surface. However, the Pt foil supported FeO2 nanostructures can be more deeply reduced to the state close to metallic Fe in 1.0 mbar H-2 at RT. The close-packed Pt(111) surface exhibits a stronger confinement effect on the FeO overlayer than the open polycrystalline Pt surface.
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