Structure of the (001)- and (111)-oriented surfaces of the ordered fcc<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Pt</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Sn alloy by low-energy-electron-diffraction intensity analysis

Atrei, A.; Bardi, Ugo; Rovida, G.; Torrini, Marco; Zanazzi, E.; Ross, Philip N.

doi:10.1103/physrevb.46.1649

Cited by 59 publications

(26 citation statements)

References 20 publications

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“…38 Bardi and co-workers have measured the outward buckling of Sn on the surface of Pt 3 Sn(111) to be 0.21Ϯ0.08 Å with reference to the plane passing through the platinum atoms, 38 and we have calculated this value to be 0.19 Å. In general, the platinum atoms bonded to the adsorbate move upward upon adsorption, while the rest of the platinum or tin atoms move downward toward the metal slab.…”

Section: Resultsmentioning

confidence: 99%

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Density functional theory studies of the adsorption of ethylene and oxygen on Pt(111) and Pt3Sn(111)

Watwe

Cortright

Mavrikakis

et al. 2001

The Journal of Chemical Physics

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Density functional theory, employing periodic slab calculations, was used to investigate the interactions of ethylene and oxygen with Pt͑111͒ and Pt 3 Sn(111). The predicted energetics and structures of adsorbed species on Pt͑111͒ are in good agreement with experimental data. The binding energies of -bonded ethylene, di--bonded ethylene, and ethylidyne species are weaker on Pt 3 Sn(111) than on Pt͑111͒ by 21, 31, and 50 kJ/mol, respectively. Hence, the electronic effect of Sn on the adsorption of ethylene depends on the type of adsorption site, with adsorption on three-fold site weakened more than adsorption on two-fold and one-fold sites. Oxygen atoms bond as strongly on Pt 3 Sn(111) as on Pt͑111͒, and these atoms prefer to adsorb near Sn atoms on the surface. The addition of Sn to Pt͑111͒ leads to a surface heterogeneity, wherein ethylidyne species prefer to adsorb away from Sn atoms and oxygen atoms prefer to adsorb near Sn atoms. Implications of this surface heterogeneity on hydrocarbon reaction selectivity on Pt-based catalysts are discussed.

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Section: Resultsmentioning

confidence: 99%

“…37 The calculated equilibrium lattice constant for the Pt 3 Sn bulk alloy is 4.08 Å, while the experimental value is 4.00 Å. 38 We have used a 2ϫ2 unit cell to study the adsorption of various species, corresponding to 1 4 monolayer coverage. Adsorption occurs on one side of the slab.…”

Section: Computational Detailsmentioning

confidence: 99%

Density functional theory studies of the adsorption of ethylene and oxygen on Pt(111) and Pt3Sn(111)

Watwe

Cortright

Mavrikakis

et al. 2001

The Journal of Chemical Physics

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“…In the early studies by qualitative LEED a c(2x2) bulk termination structure was observed, but also a a "streaked" LEED pattern was reported [20,30,32]. The structure of the c(2x2) phase was found by quantitative LEED to correspond to a simple bulk termination model, as expected [17]. The later STM studies [27] showed that the streaked pattern originates from mesoscopic features, "pyramids" on a relatively flat surface.…”

Section: Pt¢ Sn(001)mentioning

confidence: 68%

“…The atomic structure of this surface was studied by Atrei et. al [17] by quantitative LEED and found to correspond indeed to a simple bulk termination model. The other possible termination, the (A ¦ ¥ B A ¦ D R30E , was reported and studied in detail by Atrei et al [33] who also determined the atomic structure by means of quantitative LEED and found it to correspond to a single layer surface alloy.…”

Section: Pt¢ Sn(111)mentioning

confidence: 71%

“…When the difference in atomic numberand hence in the electron density -is not so large, the sensitivity to composition worsens considerably. However, a composition profile for the first 2-3 atomic layers from the topmost surface could still be obtained for transition elements in adjacent rows of the periodic table, such as the Pt-Sn system considered here [17]. In LEED it is also possible to analyse the angular distribution of the intensity of single diffracted beams (spot profile analysis LEED, SPA-LEED) in order to obtain information on the domain structure of the surface under study, as it has been done for the Pt¢ Sn(111) surface [18].…”

Section: Methodsmentioning

confidence: 99%

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Surface alloys and alloy surfaces: the platinum-tin system

Speller

Bardi

2002

Surface Alloys and Alloys Surfaces

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Ex‐situ surface preparation and analysis: transfer betweenUHVand electrochemical Cell

Hoster¹,

Gasteiger²

2010

Handbook of Fuel Cells

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The further optimization of electrode materials for fuel cells in laboratory studies offers two main approaches: (i) improving the understanding of the microscopic electrode processes by observation with in‐situ and ex‐situ methods; and (ii) the systematic compositional and structural variation of surfaces to create model electrodes for electrocatalytic measurements. The ultra high vacuum (UHV) environment offers unique possibilities for both surface preparation and analysis and has thus been used extensively in recent electrocatalytical research work. At the same time, methods allowing the in‐situ observation of electrochemical processes has also gone through impressive advances in recent years, and in many cases it has been found that earlier ex‐situ results obtained in UHV needed to be revised due to changes of the electrode surfaces during the transfer into UHV. In the following we will discuss some of the most frequently applied ex‐situ methods in electrocatalytic research and review some of the important aspects concerning the reliability of the resulting data. Utilizing a number of examples, we will demonstrate how such combined UHV electrochemistry experiments can be technically realized, including a discussion of commonly encountered practical problems. We will further point out the advantages offered by the electrocatalytical characterization of UHV designed and UHV characterized model electrodes. In our opinion, this is a very promising approach to UHV/electrochemistry experimentation: on the one hand, the uncertainties due to the transfer between UHV and electrochemical environment are less significant compared to emersion experiments of adsorbed adlayers; on the other hand, well‐established UHV preparation techniques combined with structural characterization tools (atomic force microscopy (AFM)/scanning tunneling microscopy (STM)) provide the possibility of precisely tailoring defined model electrodes. Some examples from research on anode catalysts are given to illustrate this unique capability of UHV electrochemistry setups as powerful tool for the systematic tailoring of model electrodes.

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Structure of the (001)- and (111)-oriented surfaces of the ordered fccPt3Sn alloy by low-energy-electron-diffraction intensity analysis

Cited by 59 publications

References 20 publications

Density functional theory studies of the adsorption of ethylene and oxygen on Pt(111) and Pt3Sn(111)

Density functional theory studies of the adsorption of ethylene and oxygen on Pt(111) and Pt3Sn(111)

Surface alloys and alloy surfaces: the platinum-tin system

Ex‐situ surface preparation and analysis: transfer betweenUHVand electrochemical Cell

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