Mesoscopic Self-Organization Induced by Intrinsic Surface Stress on Pt(110)

Hanesch, P.; Bertel, E.

doi:10.1103/physrevlett.79.1523

Cited by 48 publications

(33 citation statements)

References 23 publications

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“…Atomically-resolved images of the ͑2ϫ1͒-p2mg-2CO structure created on the flat terraces allow us to confidently conclude that the pressure gap has indeed been bridged for this system. Contrary to the findings of McIntyre et al we do, however, not observe any large-scale changes, i.e., the wellknown mesoscopic ''corrugated-iron'' structure 47,48 is not modified even after overnight exposure to 1 bar CO at 373 K. The level of gas cleanliness may be the point where the study of McIntyre et al differs from the present study and could explain the discrepancies.…”

Section: B High-coverage Behaviorcontrasting

confidence: 86%

CO-induced restructuring of Pt(110)-(1×2): Bridging the pressure gap with high-pressure scanning tunneling microscopy

Thostrup

Vestergaard

et al. 2003

The Journal of Chemical Physics

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We present an extensive investigation of CO-induced structural transformations occurring on the reconstructed Pt(110)-(1×2) surface while bridging the so-called pressure gap between surface science and industrial catalysis. The structural changes are followed on the atomic scale as a function of CO pressure over 12 orders of magnitude, up to 1 bar, by the use of a novel high-pressure scanning tunneling microscope (HP-STM). The transition between the low-coverage and saturation-coverage structures is found to proceed through local displacements of substrate Pt atoms. The structural transformations of the Pt surface as observed by STM can be explained within a very simple picture governed by the gain in CO binding energy when CO binds to low-coordinated metal atoms.

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Section: B High-coverage Behaviorcontrasting

confidence: 86%

CO-induced restructuring of Pt(110)-(1×2): Bridging the pressure gap with high-pressure scanning tunneling microscopy

Thostrup

Vestergaard

et al. 2003

The Journal of Chemical Physics

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“…The mesoscopic morphology of (1 2)-Pt(110) surface consists of islands elongated in the 110 Â Ã direction and characterized by varying degrees of the typical fish-scale reconstruction. [19] The rect-TiO 2 and rect'-TiO 2 overlayers were grown in the same conditions, that is, by depositing Ti at room temperature (RT) by means of an electron beam evaporator in an oxygen partial pressure of 1 10 À4 Pa, followed by a post-annealing treatment in the temperature range of 800-900 K and cooling down in oxygen (p(O 2 ) = 1 10 À4 Pa) to improve the long-range order of the deposited layer, and to allow the complete oxidation of Ti. The estimated deposition rate resulting from this treatment was % 0.075 nm min…”

Section: Experimental and Computational Sectionmentioning

confidence: 97%

Stability of TiO₂ Polymorphs: Exploring the Extreme Frontier of the Nanoscale

et al. 2010

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The structure of two ordered stoichiometric TiO(2) nanophases supported on Pt(111) and (1x2)-Pt(110) substrates, prepared by reactive evaporation of Ti in a high-oxygen background, is compared by discussing experimental data (i.e. low-energy electron diffraction, scanning tunneling microscopy) and density functional theory calculations. Two rectangular phases, called rect-TiO(2) and rect'-TiO(2) were obtained on both the hexagonal Pt(111) and the rectangular (1x2)-Pt(110) substrates, generally suggesting that they are weakly interacting with the substrates. The rect-TiO(2) phase is actually confined to a TiO(2) double layer, while the rect'-TiO(2) can extend up to a thickness of several layers and is obtained when higher Ti doses are evaporated. While the rect-TiO(2) is best described as a thickness-limited lepidocrocite-like nanosheet, growing as a single-domain-commensurate (14x4) phase on (1x2)-Pt(110) and as a six-domains-incommensurate phase on Pt(111), the thicker rect'-TiO(2) phase can be best described as a TiO(2)(B) supported nanolayer (NL). This represents the first example of the TiO(2)(B) phase in the form of a supported NL, whose properties are still largely unexplored. The important point is that, because of the weak interaction between the oxide NLs and the Pt surfaces, the substrate does not play a role in stabilizing the 2D nanostructures. Rather, it acts as a sort of lab bench where sub-nanosized titania crystallites self-assemble, so that the final NLs are representative of 2D confined titania at the bottom of the nanoscale.

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“…In most cases, the steps appear for entropic or kinetic reasons, but in certain cases like Pt(110) they might even appear for energetic reasons [52]. The metal atoms at the atomic steps have smaller coordination to fellow surface-metal atoms and hence a smaller d-band width is calculated for these atoms.…”

Section: Surface Stepsmentioning

confidence: 99%

Special Sites at Noble and Late Transition Metal Catalysts

2006

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An overview of recent advancements in density functional theory modeling of particularly reactive sites at noble and late transition metal surfaces is given. Such special sites include sites at the flat surfaces of thin metal films, sites at stepped surfaces, sites at the metal/oxide interface boundary for oxide-supported metal clusters, and sites at the perimeter of oxide islands grown on metal surfaces. The Newns-Anderson model of the electronic interaction underlying chemisorption is described. This provides the grounds for introducing the Hammer-Nørskov d-band model that correlates changes in the energy center of the valence d-band density of states at the surface sites with their ability to form chemisorption bonds. A reactivity change described by this model is characterized as an electronic structure effect. Brønsted plots of energy barriers versus reaction energies are discussed from the surface reaction perspective and are used to analyze the trends in the calculated changes. Deviations in the relation between energy barriers and reaction energies in Brønsted plots are identified as due to atomic structure effects. The reactivity change from pure Pd surfaces to Pd thin films supported on MgO can be assigned to an electronic effect. Likewise for the reactivity change from flat Au surfaces, over Au thin films to Au edges and the Au/MgO interface boundary. The reactivity enhancement at atomic step sites is of both electronic and atomic structure nature for NO dissociation at Ru, Rh and Pd surfaces. The enhancement of the CO oxidation reactivity when moving from a CO+O coadsorption structure on Pt(111) to the PtO 2 oxide island edges supported by Pt (111) is, however, identified as mainly an atomic structure effect. As such, it is linked to the occurrence of favorable pathways at the oxide island edges and is occurring despite of stronger adsorbate binding of the oxygen within the oxide edge, i.e. despite of an opposing electronic effect. As a final topic, a discussion is given of the accuracy of density functional theory in conjunction with surface reactions; adsorption, desorption, diffusion, and dissociation. Energy barriers are concluded to be more robust with respect to changes in the exchange-correlation functional than are molecular bond and adsorption energies.Theoretical modeling of heterogeneous catalysis can be approached in a number of ways with focus on different physico-chemical processes. The most fundamental process is the bond-breaking and bond-making of the individual molecules at the surface. However, topics such as the physical appearance of the solid surface (e.g. its degree of oxidation or corrugation), the interaction at the surface of reactants, reaction intermediates, and products (e.g. the degree to which they form ordered surface structures), and the flow of reactants towards the surface and of products away from the surface are other important fundamental processes. In the present review, the emphasis will be on the quantum mechanical modeling of the reaction energy profiles for s...

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Mesoscopic Self-Organization Induced by Intrinsic Surface Stress on Pt(110)

Cited by 48 publications

References 23 publications

CO-induced restructuring of Pt(110)-(1×2): Bridging the pressure gap with high-pressure scanning tunneling microscopy

CO-induced restructuring of Pt(110)-(1×2): Bridging the pressure gap with high-pressure scanning tunneling microscopy

Stability of TiO₂ Polymorphs: Exploring the Extreme Frontier of the Nanoscale

Special Sites at Noble and Late Transition Metal Catalysts

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Mesoscopic Self-Organization Induced by Intrinsic Surface Stress on Pt(110)

Cited by 48 publications

References 23 publications

CO-induced restructuring of Pt(110)-(1×2): Bridging the pressure gap with high-pressure scanning tunneling microscopy

CO-induced restructuring of Pt(110)-(1×2): Bridging the pressure gap with high-pressure scanning tunneling microscopy

Stability of TiO2 Polymorphs: Exploring the Extreme Frontier of the Nanoscale

Special Sites at Noble and Late Transition Metal Catalysts

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Product

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Stability of TiO₂ Polymorphs: Exploring the Extreme Frontier of the Nanoscale