Ordered oxygen phases on a surface

Schwarz, E.; Ernst, Karl‐Heinz; Gonser‐Buntrock, C.; Neuber, M.; Christmann, K.

doi:10.1016/0042-207x(90)90303-g

Cited by 28 publications

(14 citation statements)

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“…2(b). The ideal coverage Oj of the species giving rise to the depressions is 0.5 in agreement with the oxygen coverage postulated previously for the c(2x4) [16], thus suggesting that the oxygen mesh has been imaged by the dark circles. This interpretation is supported by the fact that 0</ increases to 1.0, when the high coverage (2x1) phase (0 = 1.0) develops upon further oxygen exposure [ Fig.…”

supporting

confidence: 88%

“…This leads to the interesting question of whether due to the structural relationship between hep (lOlO) and fee (110) surfaces analogous reconstruction behavior arises. Three different LEED superstructures were observed upon oxygen adsorption on Co(10T0) [16]: A c(2x4) phase is stable between 230 and 350 K and transforms irreversibly to a (2x1), when heated above 350 K; both overlayers exhibit equal oxygen coverages of 0= j. Further oxygen exposure to both phases leads to a (2x1) with a glide symmetry plane along [1210] as can be concluded from the missing fractional order spots («+ y,0){rt=0, ± 1, .…”

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confidence: 99%

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Oxygen adsorption on Co(101¯0): Different reconstruction behavior of hcp (101¯0) and fcc(110)

et al. 1993

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Co(lOTO) with close-packed rows separated by the oaxis distance is a hep analog to fee (110). In contrast to the (2x1) missing-row (MR) structures formed upon oxygen adsorption on several fee (110) surfaces, a novel type of MR reconstruction is revealed by scanning tunnel microscopy and low energy electron diffraction on Co(lOTO): The low coverage (2x1) O phase constitutes a double-layer MR structure with (2*1) MR configurations in the two topmost Co layers; it develops locally by moving every other atom of the topmost close-packed Co rows into respective short bridge sites of the layer underneath. Results on the c(2x4) and the high coverage (2x1) oxygen phases support this conclusion.

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confidence: 88%

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confidence: 99%

Oxygen adsorption on Co(101¯0): Different reconstruction behavior of hcp (101¯0) and fcc(110)

et al. 1993

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“…Discrepancies still exist on the vertical positions and the site specificity of the oxygen adsorbates. In an earlier LEED study, Schwarz et al [184] found that the Co(101 -0)-(2Â1)p2mg-2O phase is developed from the p(2Â1)-O or the c(2Â4)-4O phase by increasing the oxygen coverage at higher temperature. Based on the STM observations, Koch et al [42,43] proposed several models for the reconstructed O-Co(101 -0)…”

Section: Discussionmentioning

confidence: 99%

Oxidation electronics: bond–band–barrier correlation and its applications

Sun

2003

Progress in Materials Science

215

167

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“…In addition there is a vibrational feature at 2077 cm -1 from background carbon monoxide (CO) adsorbed to Pt(111). The top spectrum is obtained after exposing the Co film to oxygen, which shows two features at 359 and 548 cm -1 , similar to the t(Co-O) bond vibrations observed on Co(1010) by Schwarz et al [39]. These two spectra demonstrate the ability for HREELS to detect the change in the surface element that oxygen is bound to.…”

Section: Experimental Verificationmentioning

confidence: 71%

Theoretical Prediction and Experimental Verification of Stability of Pt–3d–Pt Subsurface Bimetallic Structures: From Single Crystal Surfaces to Polycrystalline Films

Menning

Chen

2010

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In this paper we will provide a review of our recent studies on the general stability of the Pt-3d-Pt (3d = Ti, V, Cr, Mn, Fe, Co and Ni) subsurface structures, which are the desirable structural configurations in several applications in heterogeneous catalysis and electrocatalysis. We will first provide a review of density functional theory (DFT) predictions of the thermodynamic stability of Pt-3d-Pt(111) and Pt-3d-Pt(100) in vacuum and with adsorbed hydrogen and oxygen. The DFT results predict that the Pt-3d-Pt subsurface structures are stable in vacuum and with adsorbed hydrogen, while with adsorbed oxygen the 3d atoms should segregate to the surface to produce the 3d-Pt-Pt surface structures. The DFT predictions are verified experimentally on selected Pt-3d-Pt(111) systems. The experimental efforts are further expanded by bridging the materials gap form single crystal Pt(111) to polycrystalline Pt to incorporate multiple crystal facets and to determine their effects on the kinetic barriers for the segregation of the subsurface 3d atoms. In order to further correlate DFT calculations with experimental results, a Brønsted-Evans-Polanyi relationship is derived to correlate thermodynamic stability from DFT calculations with kinetic barriers from experimental measurements for the Pt-3d-Pt systems. Finally, empirical equations have been developed for predicting the thermodynamic stability of other bimetallic systems both in vacuum and with adsorbed hydrogen and oxygen.

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Ordered oxygen phases on a surface

Cited by 28 publications

References 10 publications

Oxygen adsorption on Co(101¯0): Different reconstruction behavior of hcp (101¯0) and fcc(110)

Oxygen adsorption on Co(101¯0): Different reconstruction behavior of hcp (101¯0) and fcc(110)

Oxidation electronics: bond–band–barrier correlation and its applications

Theoretical Prediction and Experimental Verification of Stability of Pt–3d–Pt Subsurface Bimetallic Structures: From Single Crystal Surfaces to Polycrystalline Films

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