XPS and XAES study for oxidation of V/Cu(100) and V,Na/Cu(100) surfaces

Kishi, Kosaku; Hirai, Katsunori; Yamamoto, Tsuyoshi

doi:10.1016/0039-6028(93)90715-v

Cited by 31 publications

(21 citation statements)

References 31 publications

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“…The BEs for O 1s and V 2p 3/2 are 530.4 and 515.5 eV, respectively. These suggest the formation of V 2 O 3 compared with reported BEs of O 1s and V 2p 3/2 for different vanadium oxides [5][6][7][8][9][10][11]. After several annealing treatments in oxygen ambient, a hexagonal LEED pattern can be observed (not shown here).…”

Section: Oxidation Of V On Cr 2 O 3 (0001) Filmsupporting

confidence: 72%

“…The development of the line-shape with increasing vanadium coverage shows that the V 2p 3/2 photoemission signal has a shoulder centred at 515.2 eV. It is well known that the V 2p 3/2 core-level BEs for bulk V 2 O 5 , VO 2 , V 2 O 3 , VO and metallic V are 516.9, 516.2, 515.7, 515.1 and 512.2 eV, respectively [5][6][7][8][9][10][11], so the broad features at 515.2 eV at coverage of 0.1 MLE vanadium in the present work can be attributed to V 3+ or V 2+ cations at the interface. The peak of V 2p 3/2 at 512.6 eV, gradually becoming dominant at the vanadium coverage above 1 MLE, reveals that most of the vanadium on the substrate is metallic with part of the vanadium in an oxide state.…”

Section: Methodsmentioning

confidence: 99%

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Power-Dependent Coupling Characteristics of a Butt Joint between a Single-Mode Planar Waveguide and a Nonlinear Planar Waveguide with Different Film Thickness

Ono

Sakai

Osawa

et al. 1992

Jpn. J. Appl. Phys.

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The interactions of V with Cr 2 O 3 (0001) films and Cr with V 2 O 3 (0001) films at room temperature are studied using x-ray photoelectron spectroscopy and low-energy-electron diffraction. The results show that the deposited V is oxidized and the Cr 2 O 3 (0001) surface is reduced at the initial coverage due to the interaction of V with the Cr 2 O 3 substrate; V becomes metallic at V coverage greater than 5 monolayer equivalent. Full oxidization of the deposited vanadium cannot be achieved by O 2 exposure at room temperature for 20 min. However, V 2 O 3 (0001) films have been observed after heating the sample to 600-700 K in oxygen ambient at 1 × 10 −7 mbar. Similar results have been obtained for the Cr/V 2 O 3 (0001)/Re(0001) system.

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Section: Oxidation Of V On Cr 2 O 3 (0001) Filmsupporting

confidence: 72%

Section: Methodsmentioning

confidence: 99%

Power-Dependent Coupling Characteristics of a Butt Joint between a Single-Mode Planar Waveguide and a Nonlinear Planar Waveguide with Different Film Thickness

Ono

Sakai

Osawa

et al. 1992

Jpn. J. Appl. Phys.

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“…29 Furthermore, vanadia in the oxidation state +3 turns out to be the oxide that preferentially grows under typical UHV conditions such as those applied in the present study. Even the choice of the substrate seems to have only a minor impact on the oxidation state as deduced from corresponding experiments found in the literature: Cu(110), 30 Au (111) and TiO 2 (110). 3 It is important to note, however, that the structure of the vanadia overlayer prepared in this way does not necessarily reflect the bulk V 2 O 3 structure.…”

Section: Resultsmentioning

confidence: 81%

Model Catalyst Studies on Vanadia Particles Deposited onto a Thin-Film Alumina Support. 1. Structural Characterization

et al. 2002

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A model system of alumina-supported vanadia particles, representing catalysts of the type oxide 1 /oxide 2 , was prepared under ultrahigh vacuum (UHV) conditions and characterized regarding its structural and electronic properties. As supporting oxide we used a thin, well-ordered alumina film grown on NiAl(110), which allows the application of scanning tunneling microscopy (STM), infrared reflection-absorption spectroscopy (IRAS), and X-ray photoelectron spectroscopy (XPS) without charging effects. Vanadium oxide particles were prepared via metal evaporation in an oxygen ambient, leading to the growth of small, roundish oxide particles with vanadium in the +3 oxidation state. The particles are shown to interact strongly with the alumina support, resulting in an increased alumina film thickness and a distortion of the alumina film structure. IR absorption signals of the deposits could be successfully assigned to specific V-containing species, thus providing insight into the inner structure of the particles. The species identified are surface-localized vanadyl groups (VdO), interface-localized vibrations involving V, O, and Al ions, and lattice structures typical of bulk V 2 O 3 .

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“…1 From the viewpoint of surface chemistry, they constitute well-known catalysts for the oxidation of hydrocarbons and of SO 2 to SO 3 , for the removal of NO x by selective reduction with NH 3 , and for other reactions. 2 Thin layers of V oxide on metal surfaces have been prepared on Au͑111͒, 3 Cu͑100͒, 4 Ni͑110͒, 5,6 and Rh͑111͒ substrate surfaces. 7 These studies have concentrated on questions concerning the oxide preparation and surface chemistry related aspects.…”

Section: Introductionmentioning

confidence: 99%

Growth and structure of ultrathin vanadium oxide layers on Pd(111)

et al. 2000

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The growth of thin vanadium oxide films on Pd͑111͒ prepared by reactive evaporation of vanadium in an oxygen atmosphere has been studied by scanning tunneling microscopy ͑STM͒, low-energy electron diffraction ͑LEED͒, and ab initio density-functional-theory ͑DFT͒ calculations. Two-dimensional ͑2D͒ oxide growth is observed at coverages below one-half of a monolayer ͑ML͒, displaying both random island and step-flow growth modes. Above the critical coverage of 0.5 ML, three-dimensional oxide island growth is initiated. The morphology of the low-coverage 2D oxide phase depends strongly on the oxide preparation conditions, as a result of the varying balance of the mobilities of adspecies on the substrate terraces and at the edges of the growing oxide islands. Under typical V oxide evaporation conditions of p(O 2)ϭ2ϫ10 Ϫ7 mbar, T͑substrate͒ ϭ523 K, the 2D oxide film exhibits a porous fractal-type network structure with atomic-scale ordered branches, showing a p(2ϫ2) honeycomb structure. Ab initio DFT total-energy calculations reveal that a surface oxide model with a formal V 2 O 3 stoichiometry is energetically the most stable configuration. The simulated STM images show a (2ϫ2) honeycomb structure in agreement with experimental observation. This surface-V 2 O 3 layer is very different from bulk V 2 O 3 and represents an interface stabilized oxide structure. The V oxide layers decompose on annealing above 673 K and 2D island structures of V/Pd surface alloy and metallic V are then formed on the Pd͑111͒ surface.

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XPS and XAES study for oxidation of V/Cu(100) and V,Na/Cu(100) surfaces

Cited by 31 publications

References 31 publications

Power-Dependent Coupling Characteristics of a Butt Joint between a Single-Mode Planar Waveguide and a Nonlinear Planar Waveguide with Different Film Thickness

Power-Dependent Coupling Characteristics of a Butt Joint between a Single-Mode Planar Waveguide and a Nonlinear Planar Waveguide with Different Film Thickness

Model Catalyst Studies on Vanadia Particles Deposited onto a Thin-Film Alumina Support. 1. Structural Characterization

Growth and structure of ultrathin vanadium oxide layers on Pd(111)

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