Generation of atomic oxygen on Ag(111) and Ag(110) using NO2: a TPD, LEED, HREELS, XPS and NRA study

Bare, Simon R.; Griffiths, K.; Lennard, W. N.; Hong, Tao

doi:10.1016/0039-6028(95)00670-2

Cited by 133 publications

(111 citation statements)

References 36 publications

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“…All TPD measurements were performed with a ramp rate of 3 K s -1 . (6,22). For these reasons, NO 2 oxidation provides a convenient calibration method for the uptake of oxygen during AO exposures.…”

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confidence: 99%

Thermally Selective Formation of Subsurface Oxygen in Ag(111) and Consequent Surface Structure

et al. 2016

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Derouin, Jonathan; Farber, Rachael G.; Turano, Marie E.; Iski, Erin V.; and Killelea, Daniel. Thermally Selective Formation of Subsurface Oxygen in Ag(111) Just Accepted "Just Accepted" manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides "Just Accepted" as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. "Just Accepted" manuscripts appear in full in PDF format accompanied by an HTML abstract. "Just Accepted" manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). "Just Accepted" is an optional service offered to authors. Therefore, the "Just Accepted" Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the "Just Accepted" Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these "Just Accepted" manuscripts. Thermally Selective Formation of Subsurface Oxygen inAg (111) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 AbstractA long-standing challenge in the study of heterogeneously catalyzed reactions on silver surfaces has been the determination of what oxygen species are of greatest chemical importance.This is due to the coexistence of several different surface phases on oxidized silver surfaces. A further complication is subsurface oxygen (O sub ). O sub are O atoms absorbed into the near surface of a metal, and are expected to alter the surface in terms of chemistry and structure, but these effects have yet to be well characterized. We studied oxidized Ag(111) surfaces after exposure to gas-phase O atoms to determine how O sub is formed and how its presence alters the resultant surface structure. Using a combination of surface science techniques to quantify O sub formation and the resultant surface structure, we observed that once 0.1 ML of O sub has formed, the surface dramatically, and uniformly, reconstructed to a striped phase at the expense of all other surface phases. Furthermore, O sub formation was hindered at temperatures above 500 K.The thermal dependence for O sub formation suggests that at industrial catalytic conditions of 475 -500 K for the epoxidation of ethylene-to-ethylene oxide, O sub would be present and is a factor in the subsequent reactivit...

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Thermally Selective Formation of Subsurface Oxygen in Ag(111) and Consequent Surface Structure

et al. 2016

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“…The Ag(111) sample was cleaned by repeated Ar þ sputtering and annealing to 773 K for 30 min until a sharp (1 Â 1) low-energy electron diffraction pattern was observed and the surface was free of any contaminant as measured by m-probe XPS. NO 2 (99.0 vol %) was dosed following a known recipe 14 . A capillary was placed with its opening close to the sample surface to minimize the amount of gas in the vacuum system.…”

Section: Methodsmentioning

confidence: 99%

“…The parameters used in equation (3) were the following. The reactive sticking coefficient s 0 of NO 2 on Ag(111) is known to be high 14 , and we assumed a value of unity. p(NO 2 ) was the ion gauge reading, corrected by a factor 1/20, because the mass spectrometer indicated considerable decomposition of NO 2 at the chamber walls, so that a part of the total pressure was caused by NO.…”

Section: Methodsmentioning

confidence: 99%

“…Oxygen was adsorbed on Ag(111) by dosing NO 2 at T Z450 K. NO 2 decomposes into oxygen atoms and NO, and the NO desorbs. This method avoids the large gas exposures required when O 2 is used 14 . The adsorbed O atoms form an ordered surface structure with a (4 Â 4) lattice.…”

Section: Combination Of Leem and Tpdmentioning

confidence: 99%

“…The system studied, adsorbed oxygen atoms on an Ag(111) surface, is known for its strong desorption anomalies in TPD, namely, the O 2 desorption peak does not show the shift to lower temperature with initial O coverage expected for recombinative desorption, and it can split into two peaks [13][14][15] . The binding of oxygen to silver surfaces plays an important role in the Ag-catalysed synthesis of ethylene oxide 16,17 .…”

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confidence: 99%

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Desorption kinetics from a surface derived from direct imaging of the adsorbate layer

et al. 2014

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There are numerous indications that adsorbed particles on a surface do not desorb statistically, but that their spatial distribution is important. Evidence almost exclusively comes from temperature-programmed desorption, the standard method for measuring desorption rates. However, this method, as a kinetics experiment, cannot uniquely prove an atomic mechanism. Here we report a low-energy electron microscopy investigation in which a surface is microscopically imaged while simultaneously temperature-programmed desorption is recorded. The data show that during desorption of oxygen molecules from a silver single crystal surface, islands of oxygen atoms are present. By correlating the microscopy and the kinetics data, a model is derived that includes the shapes of the islands and assumes that the oxygen molecules desorb from the island edges. The model quantitatively reproduces the complex desorption kinetics, confirming that desorption is affected by islands and that the often used mean-field treatment is inappropriate.

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Silver‐Mediated Oxidation Reactions: Recent Advances and New Prospects

Li¹,

Capretto²,

He³

2009

Progress in Inorganic Chemistry

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Generation of atomic oxygen on Ag(111) and Ag(110) using NO2: a TPD, LEED, HREELS, XPS and NRA study

Cited by 133 publications

References 36 publications

Thermally Selective Formation of Subsurface Oxygen in Ag(111) and Consequent Surface Structure

Thermally Selective Formation of Subsurface Oxygen in Ag(111) and Consequent Surface Structure

Desorption kinetics from a surface derived from direct imaging of the adsorbate layer

Silver‐Mediated Oxidation Reactions: Recent Advances and New Prospects

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