The adsorption of water on clean and oxygen-dosed Ru(011)

Interactions of thermally and electronically stimulated reactions in thin layers on surfaces are investigated. For self-assembled monolayers, thermal activation promotes many processes primarily induced by electronic excitations. We demonstrate that the film temperature is an important parameter for steering these reactions towards different final products. Using chemisorbed water on Ru(001) as an example, we investigate how the products of an irradiation induced reaction catalyze thermally stimulated dissociation of water molecules. PACS

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“…Co-adsorbed hydrogen has the inverse effect. Clay's data are in qualitative agreement with previous results from Doering and Madey [23].…”

Section: Beam Induced Conversion Of Water Layers Onsupporting

confidence: 90%

Electronically induced modification of thin layers on surfaces

Bauer

Neppl

Menzel

et al. 2007

Low Temperature Physics

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“…Dissociation is observed at low oxygen coverage ͑ Ͻ 0.2 ML͒ while it is inhibited at larger O coverage ͑ = 0.25-0.5 ML͒ contrary to studies that assume that water remains intact when interacting with oxygen. [6][7][8][9] Preadsorbed oxygen on the ruthenium surface does not only influence the dissociation characteristics of water but also its structure. On the p͑2 ϫ 2͒ oxygen terminated surface, water adsorbs in a p͑2 ϫ 2͒ symmetry, 4,10 compared to a hexagonal arrangement ͑ͱ3 ϫ ͱ 3͒R30°observed on clean hexagonalclose-packed metal surfaces.…”

Section: Introductionmentioning

confidence: 99%

Water-induced surface reconstruction of oxygen(2×1)covered Ru(0001)

et al. 2010

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Low-temperature scanning tunneling microscopy and density-functional theory ͑DFT͒ were used to study the adsorption of water on a Ru͑0001͒ surface covered with half monolayer of oxygen. The oxygen atoms occupy hcp sites in an ordered structure with ͑2 ϫ 1͒ periodicity. DFT predicts that water is weakly bound to the unmodified surface, 86 meV compared to the ϳ200 meV water-water H bond. Instead, we found that water adsorption causes a shift of half of the oxygen atoms from hcp sites to fcc sites, creating a honeycomb structure where water molecules bind strongly to the exposed Ru atoms. The energy cost of reconstructing the oxygen overlayer, around 230 meV per displaced oxygen atom, is more than compensated by the larger adsorption energy of water on the newly exposed Ru atoms. Water forms hydrogen bonds with the fcc O atoms in a ͑4 ϫ 2͒ superstructure due to alternating orientations of the molecules. Heating to 185 K results in the complete desorption of the water layer, leaving behind the oxygen-honeycomb structure, which is metastable relative to the original ͑2 ϫ 1͒. This stable structure is not recovered until after heating to temperatures close to 260 K.

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“…In addition, the great abundance of water, ice and water-covered solid surfaces in the biosphere explains the attention devoted to the study of water adsorption on single crystal surfaces by means of modern surface science techniques [31,32]. In particular, for H 2 O/Ru(0001), the possible structures water can form, from adsorbed isolated molecules to small clusters, periodic bilayers or ice multilayers were extensively studied during 20 years since the late 1970s through a wide variety of experimental techniques [27,[33][34][35][36][37][38][39]. The basic findings were: (i) three distinct water peaks in the thermal desorption spectra (TDS), one at low temperature (150 ∼ 160 K) attributed to ice multilayers, and two at higher temperatures (170 ∼ 180 K, 210 ∼ 220 K) attributed to water aggregates (periodic bilayers, clusters) in more direct contact with the metal surface; (ii) an ordered (…”

Section: Water Adsorption On Ru(0001)mentioning

confidence: 99%

“…From this amount of experimental information at hand until 1982, the system appeared to be well understood, and a widely accepted model for water adsorption was proposed [34]. This model was based on the close match between the (0001) lattice of the Ru crystal and the hexagonal phase of ice (ice I h , [40]), giving rise to the highest temperature peak (the "chemisorbed" state) in the thermal desorption spectra.…”

Section: Water Adsorption On Ru(0001)mentioning

confidence: 99%

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Chemistry at surfaces: from ab initio structures to quantum dynamics

et al. 2007

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Recent years have witnessed an ever growing interest in theoretically studying chemical processes at surfaces. Apart from the interest in catalysis, electrochemistry, hydrogen economy, green chemistry, atmospheric and interstellar chemistry, theoretical understanding of the molecule-surface chemical bonding and of the microscopic dynamics of adsorption and reaction of adsorbates are of fundamental importance for modeling known processes, understanding new experimental data, predicting new phenomena, controlling reaction pathways. In this work, we review the efforts we have made in the last few years in this exciting field. We first consider the energetics and the structural properties of some adsorbates on metal surfaces, as deduced by converged, first-principles, plane-wave calculations within the slab-supercell approach. These studies comprise water adsorption on Ru(0001), a subject of very intense debate in the past few years, and oxygen adsorption on aluminum, the prototypical example of metal passivation. Next, we address dynamical processes at surfaces with classical and quantum methods. Here the main interest is in hydrogen dynamics on metallic and semi-metallic surfaces, because of its importance for hydrogen storage and interstellar chem- istry. Hydrogen sticking is studied with classical and quasi-classical means, with particular emphasis on the relaxation of hot-atoms following dissociative chemisorption. Hot atoms dynamics on metal surfaces is investigated in the reverse, hydrogen recombination process and compared to Eley-Rideal dynamics. Finally, Eley-Rideal, collision-induced desorption, and adsorbate-induced trapping are studied quantum mechanically on a graphite surface, and unexpected quantum effects are observed.

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The adsorption of water on clean and oxygen-dosed Ru(011)

Cited by 392 publications

References 21 publications

Electronically induced modification of thin layers on surfaces

Electronically induced modification of thin layers on surfaces

Water-induced surface reconstruction of oxygen(2×1)covered Ru(0001)

Chemistry at surfaces: from ab initio structures to quantum dynamics

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