Water chemisorption on a sputter deposited uranium dioxide film - Effect of defects

S. Cohen; M. H. Mintz; S. Zalkind; A. Seibert; T. Gouder; N. Shamir

doi:10.1016/j.ssi.2014.05.003

Water chemisorption on a sputter deposited uranium dioxide film - Effect of defects

S. Cohen, M. H. Mintz, S. Zalkind, A. Seibert, T. Gouder, N. Shamir

Unit of Nuclear Engineering

Research output: Contribution to journal › Article › peer-review

11 Scopus citations

Abstract

The characteristics of water vapor chemisorptions on stoichiometric and on sputtered reduced UO₂ thin film surfaces, obtained by the reactive sputter deposition technique, were studied by utilizing direct recoil spectrometry and X-ray photoelectron spectroscopy over a temperature range of 300-500 K. It seems that dissociative chemisorption takes place on both types of surfaces but surface coverage and adsorption rates are different. For the stoichiometric surface, DRS results indicate that water partially dissociate on this surface up to 350 K, probably on sparse defect sites. On the other hand, the kinetics of water dissociation fragments (H, O, OH) on the defected surface displayed a complex behavior, caused by the healing effect of surface defects, being temperature dependent. A modified water chemisorption model is proposed, assuming dense clusters of hydroxyls with a mix of perpendicular and tilted OH bonds formed on the UO_{2 - x} sputtered surface. Perpendicular isolated hydroxyls are assumed to be predominant on UO₂ stoichiometric surface.

Original language	English
Pages (from-to)	39-45
Number of pages	7
Journal	Solid State Ionics
Volume	263
DOIs	https://doi.org/10.1016/j.ssi.2014.05.003
State	Published - 1 Oct 2014

Keywords

Adsorption kinetics
Chemisorption, Surface defects
Dissociation
Hydrogen bonds

ASJC Scopus subject areas

General Chemistry
General Materials Science
Condensed Matter Physics

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title = "Water chemisorption on a sputter deposited uranium dioxide film - Effect of defects",

abstract = "The characteristics of water vapor chemisorptions on stoichiometric and on sputtered reduced UO2 thin film surfaces, obtained by the reactive sputter deposition technique, were studied by utilizing direct recoil spectrometry and X-ray photoelectron spectroscopy over a temperature range of 300-500 K. It seems that dissociative chemisorption takes place on both types of surfaces but surface coverage and adsorption rates are different. For the stoichiometric surface, DRS results indicate that water partially dissociate on this surface up to 350 K, probably on sparse defect sites. On the other hand, the kinetics of water dissociation fragments (H, O, OH) on the defected surface displayed a complex behavior, caused by the healing effect of surface defects, being temperature dependent. A modified water chemisorption model is proposed, assuming dense clusters of hydroxyls with a mix of perpendicular and tilted OH bonds formed on the UO2 - x sputtered surface. Perpendicular isolated hydroxyls are assumed to be predominant on UO2 stoichiometric surface.",

keywords = "Adsorption kinetics, Chemisorption, Surface defects, Dissociation, Hydrogen bonds",

author = "S. Cohen and Mintz, {M. H.} and S. Zalkind and A. Seibert and T. Gouder and N. Shamir",

note = "Funding Information: This work was partially supported by a grant from the collaboration between the European Joint Research Centre (JRC) and the Israel Atomic Energy Commission (IAEC) . The authors wish to thank Dr. Shmuel Hayun of BGU for a fruitful discussion.",

year = "2014",

month = oct,

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doi = "10.1016/j.ssi.2014.05.003",

language = "English",

volume = "263",

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journal = "Solid State Ionics",

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T1 - Water chemisorption on a sputter deposited uranium dioxide film - Effect of defects

AU - Cohen, S.

AU - Mintz, M. H.

AU - Zalkind, S.

AU - Seibert, A.

AU - Gouder, T.

AU - Shamir, N.

N1 - Funding Information: This work was partially supported by a grant from the collaboration between the European Joint Research Centre (JRC) and the Israel Atomic Energy Commission (IAEC) . The authors wish to thank Dr. Shmuel Hayun of BGU for a fruitful discussion.

PY - 2014/10/1

Y1 - 2014/10/1

N2 - The characteristics of water vapor chemisorptions on stoichiometric and on sputtered reduced UO2 thin film surfaces, obtained by the reactive sputter deposition technique, were studied by utilizing direct recoil spectrometry and X-ray photoelectron spectroscopy over a temperature range of 300-500 K. It seems that dissociative chemisorption takes place on both types of surfaces but surface coverage and adsorption rates are different. For the stoichiometric surface, DRS results indicate that water partially dissociate on this surface up to 350 K, probably on sparse defect sites. On the other hand, the kinetics of water dissociation fragments (H, O, OH) on the defected surface displayed a complex behavior, caused by the healing effect of surface defects, being temperature dependent. A modified water chemisorption model is proposed, assuming dense clusters of hydroxyls with a mix of perpendicular and tilted OH bonds formed on the UO2 - x sputtered surface. Perpendicular isolated hydroxyls are assumed to be predominant on UO2 stoichiometric surface.

AB - The characteristics of water vapor chemisorptions on stoichiometric and on sputtered reduced UO2 thin film surfaces, obtained by the reactive sputter deposition technique, were studied by utilizing direct recoil spectrometry and X-ray photoelectron spectroscopy over a temperature range of 300-500 K. It seems that dissociative chemisorption takes place on both types of surfaces but surface coverage and adsorption rates are different. For the stoichiometric surface, DRS results indicate that water partially dissociate on this surface up to 350 K, probably on sparse defect sites. On the other hand, the kinetics of water dissociation fragments (H, O, OH) on the defected surface displayed a complex behavior, caused by the healing effect of surface defects, being temperature dependent. A modified water chemisorption model is proposed, assuming dense clusters of hydroxyls with a mix of perpendicular and tilted OH bonds formed on the UO2 - x sputtered surface. Perpendicular isolated hydroxyls are assumed to be predominant on UO2 stoichiometric surface.

KW - Adsorption kinetics

KW - Chemisorption, Surface defects

KW - Dissociation

KW - Hydrogen bonds

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DO - 10.1016/j.ssi.2014.05.003

M3 - Article

AN - SCOPUS:84901929538

SN - 0167-2738

VL - 263

SP - 39

EP - 45

JO - Solid State Ionics

JF - Solid State Ionics

ER -

Water chemisorption on a sputter deposited uranium dioxide film - Effect of defects

Abstract

Keywords

ASJC Scopus subject areas

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