Observation of a novel high density 3O(2 × 2) structure on Ru(001)

Kostov, Konstantin; Gsell, M.; Jakob, Peter M.; Möritz, Thomas; Widdra, W.; Menzel, D.

doi:10.1016/s0039-6028(97)00787-5

Cited by 87 publications

(62 citation statements)

References 18 publications

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“…3(c), but not in Fig. 3(b), can be observed for the 3Oð2 Â 2Þ-Ruð0001Þ surface reported in [28]. This finding suggests a similar oxygen arrangement of the topmost layer of silica.…”

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confidence: 67%

Growth and Structure of Crystalline Silica Sheet on Ru(0001)

et al. 2010

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Thin SiO 2 films were grown on a Ru(0001) single crystal and studied by photoelectron spectroscopy, infrared spectroscopy and scanning probe microscopy. The experimental results in combination with density functional theory calculations provide compelling evidence for the formation of crystalline, double-layer sheet silica weakly bound to a metal substrate. DOI: 10.1103/PhysRevLett.105.146104 PACS numbers: 68.35.Àp, 68.47.Gh, 68.55.Àa Silicon dioxide (SiO 2 ) plays a key role in many modern technologies and applications that range from insulating layers in integrated circuits to supports for metal and oxide clusters in catalysts. For better understanding of structureproperty relationships on silica-based materials, particularly of reduced dimensions, thin silica films grown on metal single crystal substrates are suggested as suitable model systems that allow the facile application of many ''surface science'' techniques. It has recently been shown that crystalline silica films and nanowires can be grown on Mo(112) [1][2][3][4][5]. The ultrathin film consists of a monolayer honeycomblike network of corner-sharing [SiO 4 ] tetrahedra, thus resulting in a SiO 2:5 stoichiometry of the film. The Si atoms in these films can be partly substituted by Al in the course of preparing metal supported aluminosilicate films [6], which is the first step towards experimental modeling of catalytic centers in zeolitelike materials. However, attempts to grow thicker silica films on the Mo substrates resulted in amorphous structures [7][8][9], most likely due to the formation of strong Si-O-Mo bonds at the interface that govern the growth mode [9]. Recently, the preparation of crystalline silica films on other supports such as Pd(100) [10] and Ni(111) [11] has been reported. However, the atomic structure of the films, film surface termination, and the nature of the silica-metal interface were not determined.In this Letter, we report on the preparation and the atomic structure of well-defined silica films on Ru(0001). The experimental results, obtained by photoelectron and vibrational spectroscopies and high-resolution scanning probe microscopy, are complemented by density functional theory calculations which together provide compelling evidence for the formation of a double-layer sheet silicate, with a SiO 2 stoichiometric composition, weakly bound to a metal support. The results open new perspectives for employing a ''surface science'' approach to understand the reactivity of silicate surfaces consisting of hydrophobic Si-O-Si bonds, such as those of microporous all-silica zeolites [12]. Also, these films can be used as model supports for catalytically active metal and oxide clusters [4,13].The experiments were performed in an ultrahigh vacuum chamber equipped with low energy electron diffraction (LEED) and Auger electron spectroscopy, x-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), and scanning tunneling microscopy (STM). Atomically resolved atomic force microscopy (AFM) and STM image...

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“…3(c), but not in Fig. 3(b), can be observed for the 3Oð2 Â 2Þ-Ruð0001Þ surface reported in [28]. This finding suggests a similar oxygen arrangement of the topmost layer of silica.…”

mentioning

confidence: 67%

Growth and Structure of Crystalline Silica Sheet on Ru(0001)

et al. 2010

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“…Recent studies employing NO 2 or very high O 2 exposures have shown, however, that Ru(0 0 0 1) can support higher coverages, for example, ordered structures with H ¼ 0:75 [68][69][70] and with H ¼ 1 [71], as had initially been predicted by DFT-GGA calculations [72].…”

Section: Weakening the Adatom-surface Bondsmentioning

confidence: 84%

Catalysis and corrosion: the theoretical surface-science context

et al. 2002

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NNumerous experiments in ultra-high vacuum as well as (T ¼ 0 K, p ¼ 0) theoretical studies on surfaces have been performed over the last decades in order to gain a better understanding of the mechanisms, which, for example, underlie the phenomena of catalysis and corrosion. Often the results achieved this way cannot be extrapolated directly to the technologically relevant situation of finite temperature and high pressure. Accordingly, modern surface science has realized that bridging the so-called pressure gap (getting out of the vacuum) is the inevitable way to go. Of similar importance are studies in which the temperature is changed systematically (warming up and cooling down). Both aspects are being taken into account in recent experiments and ab initio calculations.In this paper we stress that there is still much to learn and important questions to be answered concerning the complex atomic and molecular processes which occur at surfaces and actuate catalysis and corrosion, although significant advances in this exciting field have been made over the years. We demonstrate how synergetic effects between theory and experiment are leading to the next step, which is the development of simple concepts and understanding of the different modes of the interaction of chemisorbed species with surfaces. To a large extent this is being made possible by recent developments in theoretical methodology, which allow to extend the ab initio (i.e., starting from the selfconsistent electronic structure) approach to poly-atomic complexes with 10,000 and more atoms, time scales of seconds, and involved statistics (e.g., ab initio molecular dynamics with 10,000 and more trajectories). In this paper we will 1. sketch recent density-functional theory based hybrid methods, which bridge the length and time scales from those of electron orbitals to meso-and macroscopic proportions, and 2. present some key results on properties of surfaces, demonstrating their role in corrosion and heterogeneous catalysis.In particular we discuss • the influence of the ambient gas phase on the surface structure and stoichiometry, • adsorbate phase transitions and thermal desorption, and • the role of atoms' dynamics and statistics for the surface chemical reactivity.

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“…These models are based on the well-documented O/Ru(0001)-ordered structures, such as 63 and (1 × 1)-O. 64 To simplify the nomenclature, the O-rich models are denoted by the amount of oxygen within the orthogonal (2 × 2) Ru(0001) unit cell, i.e., (SiO 2 ) 8 2O/Ru, (SiO 2 ) 8 4O/Ru, (SiO 2 ) 8 6O/Ru, and (SiO 2 ) 8 8O/Ru, respectively.…”

Section: Computational Resultsmentioning

confidence: 99%

Tuning the electronic structure of ultrathin crystalline silica films on Ru(0001)

et al. 2012

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A combination of density functional theory calculations and photoelectron spectroscopy provides new insights into the atomistic picture of ultrathin silica films grown on Ru(0001). The silica film features a double-layer silicate sheet formed by corner-sharing [SiO 4 ] tetrahedra and is weakly bound to the Ru(0001) substrate. This allows oxygen atoms to reversibly adsorb directly on the metal surface underneath the silica film. We demonstrate that the amount of adsorbed oxygen can be reversibly varied by vacuum annealing and oxidation, which in turn result in gradual changes of the silica/Ru electronic states. This finding opens the possibility for tuning the electronic properties of oxide/metal systems without altering the thickness or the structure of an oxide overlayer.

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Observation of a novel high density 3O(2 × 2) structure on Ru(001)

Cited by 87 publications

References 18 publications

Growth and Structure of Crystalline Silica Sheet on Ru(0001)

Growth and Structure of Crystalline Silica Sheet on Ru(0001)

Catalysis and corrosion: the theoretical surface-science context

Tuning the electronic structure of ultrathin crystalline silica films on Ru(0001)

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