Species formed at cuprite fracture surfaces; observation of O 1s surface core level shift

Harmer, Sarah L.; Skinner, William; Buckley, Alan N.; Fan, Liang‐Jen

doi:10.1016/j.susc.2008.12.024

Cited by 36 publications

(32 citation statements)

References 64 publications

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“…There are three other concerns related to the accuracy of BO%: (i) peak asymmetry, (ii) the existence of surface peaks on both BO and NBO + O 2− peaks, 62,63 and (iii) possible OH contamination. These have been discussed in detail in a recent review, 48 but they are worth summarizing.…”

Section: Other Contributions To Uncertaintymentioning

confidence: 99%

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Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

et al. 2015

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To resolve discrepant results between O1s XPS and 29 Si and 17 O NMR techniques, O1s XPS spectra were collected and fitted for 15 potassium silicate glasses containing 10−37 mol% K 2 O. The effects of melting on the compositions of the glasses are documented and quantified, as are uncertainties associated with fitting the O1s spectra. These spectra are well resolved into two symmetric peaks: a narrow peak due to NBO (Si−O−K) plus "free oxide" (O 2-or K−O−K) and a broader peak due to BO (Si−O−Si). Values of mol% BO (uncertainties of ±1%) are obtained from the computed peak areas and indicate 2.2 (±0.8) mol% O 2-for glasses containing 32 (±1) mol% K 2 O. Reassignment of Q species for previously published 29 Si NMR spectra leads to BO and O 2-values in good agreement with these O1s XPS spectra. A recent 17 O NMR study on potassium silicate glasses concluded that there is <1 mol% O 2-in these glasses based mainly on the assumption that the 17 O chemical shift for O 2-should be similar in the glasses and the oxide in crystalline K 2 O. This assumption is questionable. Free oxide in these glasses should be highly reactive toward gases such as CO 2 (via CO 2 + O 2-¡ CO 3 2-) and it seems likely that the reactive species in silicate glasses is O 2-rather than NBO as often assumed. The small amounts of CO 2 found in reacted glasses are qualitatively consistent with the abundance of O 2-obtained from these O1s XPS spectra of silicate glass. Key words: potassium silicate glasses, free oxide, O1s XPS, 29 Si, 17 O NMR. Résumé : Afin de résoudre les disparités entre les résultats des techniques de spectrométrie de photoélectrons XPS O1s et RMN 29 Si et 17 O, nous avons enregistré les spectres XPS O1s de 15 verres silicatés de potassium contenant de 10 à 37 mol % de K 2 O et les avons soumis à l'analyse de pic par ajustement. Les effets de la fonte sur la composition des verres sont documentés et quantifiés, ainsi que les incertitudes associées à l'analyse de pic par ajustement des spectres XPS O1s. Ces spectres montrent deux pics symétriques en bonne résolution : un pic étroit, attribuable à l'oxygène non pontant (Si−O−K) et à « l'oxyde libre » (O 2-ou K−O−K), et un pic plus large, attribuable à l'oxygène pontant (Si−O−Si). Les taux d'oxygène pontant en mol % (incertitudes de ±1 %) sont obtenus à partir des valeurs calculées de l'aire des pics et se situent à 2,2 (±0,8) mol % d'O 2-pour les verres contenant 32 (± 1) mol % de K 2 O. La redéfinition des espèces Q à partir de données spectrales RMN 29 Si déjà publiées mène à des taux d'oxygène pontant et d'O 2-en concordance avec ces spectres XPS O1s. Une récente analyse RMN 17 O portant sur des verres silicatés de potassium a permis de conclure que ces verres contenaient moins de 1 mol % d'O 2-, principalement selon l'hypothèse que le déplacement chimique de l' 17 O des atomes d'O 2-dans les verres devrait être semblable à celui des oxydes dans le K 2 O cristallin. Cette hypothèse est contestable. Dans ces verres, l'oxyde libre devrait réagir fortement avec les gaz comme le CO 2...

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Section: Other Contributions To Uncertaintymentioning

confidence: 99%

“…63 Surface signals will be present for both the BO and NBO peaks and tend to "cancel" each other during fitting of the spectra. It cannot be argued that surface contributions preferentially enhance BO signals relative to NBO signals, which would lead to abnormally high X BO and O 2− values.…”

Section: Other Contributions To Uncertaintymentioning

confidence: 99%

Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

et al. 2015

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“…The kinetic energy of O 1s photoelectrons is about 940 eV so that the topmost atomic layer should make weak surface contributions to both the BO and NBO peaks of the O 1s spectrum; to our knowledge, there has been only one study of an oxide where a surface contribution has been demonstrated [16]. The surface contribution was weak even though the synchrotron study was optimized to maximize surface contributions.…”

Section: Surface and Bulk Contributions To Xps Spectramentioning

confidence: 99%

Bridging, non-bridging and free (O2–) oxygen in Na2O-SiO2 glasses: An X-ray Photoelectron Spectroscopic (XPS) and Nuclear Magnetic Resonance (NMR) study

Nesbitt¹,

Bancroft²,

Henderson³

et al. 2011

Journal of Non-Crystalline Solids

276

169

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“…The unobserved surface O peak in uncoated SiO 2 will be at lower BE (probably ≤0.5 eV) than the bulk [23,24], so the ∼2.3 eV shift to lower BE of this peak is consistent with a shift of ∼1.8 eV in the surface peak due to the Cr bonded to each surface O atom. Fig.…”

Section: O 1s and Si 1s Narrow Scansmentioning

confidence: 75%

“…Such a linewidth is critical for the future studies of silicate glasses at high photon energies. Second, using a thin metal films on the SiO 2 , we want to quantify the increase in escape depth for SiO 2 from 1486 eV to 5000 eV photon energies, and demonstrate that we can use the O 1s and Si 1s chemical shifts created by the interface Cr-subox to indirectly determine the unknown intensity of the expected [13,23,24], but not previously observed, surface peaks. Third, we will also show that the minimum Si 1s linewidths obtained are consistent with that expected from the final state vibrational broadening mechanism outlined previously for the Si 2p and O 1s linewidths [12][13][14][15][17][18][19]].…”

Section: Introductionmentioning

confidence: 97%

Hard X-ray photoelectron spectra (HXPES) of bulk non-conductor vitreous SiO 2 : Minimum linewidths and surface chemical shifts

Xiao

Wang

et al. 2015

Journal of Electron Spectroscopy and Related Phenomena

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Species formed at cuprite fracture surfaces; observation of O 1s surface core level shift

Cited by 36 publications

References 64 publications

Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

Bridging, non-bridging and free (O2–) oxygen in Na2O-SiO2 glasses: An X-ray Photoelectron Spectroscopic (XPS) and Nuclear Magnetic Resonance (NMR) study

Hard X-ray photoelectron spectra (HXPES) of bulk non-conductor vitreous SiO 2 : Minimum linewidths and surface chemical shifts

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