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Title: The Reactions of Water Vapour on the Surfaces of Stoichiometric and Reduced Uranium Dioxide: A High Resolution XPS Study

Abstract

The reaction of water with stoichiometric and O-defective UO{sub 2} thin film surfaces is studied by high-resolution photoelectron spectroscopy using synchrotron X-rays radiation. The decomposition of D{sub 2}O molecules and the oxidative healing of defects on the reduced surfaces was observed and quantified. D{sub 2}O adsorption on the stoichiometric UO{sub 2} surface at 300 K showed small amounts of OD species (ca. 532 eV) probably formed on trace amounts of surface defects, while at 95 K D2O ice (533.5 eV) was the main surface species. On the contrary, a large signal of OD species was seen on the 300 K-Ar{sup +}-sputtered (reduced) surface, UO{sub 2-x}. This was concomitant with a rapid healing of surface defects as monitored by their U4f signal. Quantitative analysis of the OD signal with increasing temperature showed their disappearance by 550 K. The disappearance of these species while hydrogen molecules are still desorbing from the surface as monitored by TPD [S.D. Senanayake, H. Idriss, Surf. Sci. 563 (1-3) (2004) 135; S.D. Senanayake, R. Rousseau, D. Colegrave, H. Idriss, J. Nucl. Mater. 342 (2005) 179] is shedding light on the re-combinative desorption mechanism from dissociatively adsorbed water molecules on the surfaces of this defective metal oxide.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930258
Report Number(s):
BNL-80950-2008-JA
Journal ID: ISSN 0920-5861; CATTEA; TRN: US0806721
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Catalysis Today; Journal Volume: 120
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 43 PARTICLE ACCELERATORS; ADSORPTION; AUGMENTATION; DECOMPOSITION; DEFECTS; DESORPTION; HEALING; HYDROGEN; ICE; METALS; MOLECULES; PHOTOELECTRON SPECTROSCOPY; RESOLUTION; SIGNALS; SURFACES; SYNCHROTRONS; THIN FILMS; TRACE AMOUNTS; URANIUM DIOXIDE; VISIBLE RADIATION; WATER; X-RAY PHOTOELECTRON SPECTROSCOPY; national synchrotron light source

Citation Formats

Senanayake,S., Waterhouse, G., Chan, A., Madey, T., Mullins, D., and Idriss, H. The Reactions of Water Vapour on the Surfaces of Stoichiometric and Reduced Uranium Dioxide: A High Resolution XPS Study. United States: N. p., 2007. Web. doi:10.1016/j.cattod.2006.07.040.
Senanayake,S., Waterhouse, G., Chan, A., Madey, T., Mullins, D., & Idriss, H. The Reactions of Water Vapour on the Surfaces of Stoichiometric and Reduced Uranium Dioxide: A High Resolution XPS Study. United States. doi:10.1016/j.cattod.2006.07.040.
Senanayake,S., Waterhouse, G., Chan, A., Madey, T., Mullins, D., and Idriss, H. Mon . "The Reactions of Water Vapour on the Surfaces of Stoichiometric and Reduced Uranium Dioxide: A High Resolution XPS Study". United States. doi:10.1016/j.cattod.2006.07.040.
@article{osti_930258,
title = {The Reactions of Water Vapour on the Surfaces of Stoichiometric and Reduced Uranium Dioxide: A High Resolution XPS Study},
author = {Senanayake,S. and Waterhouse, G. and Chan, A. and Madey, T. and Mullins, D. and Idriss, H.},
abstractNote = {The reaction of water with stoichiometric and O-defective UO{sub 2} thin film surfaces is studied by high-resolution photoelectron spectroscopy using synchrotron X-rays radiation. The decomposition of D{sub 2}O molecules and the oxidative healing of defects on the reduced surfaces was observed and quantified. D{sub 2}O adsorption on the stoichiometric UO{sub 2} surface at 300 K showed small amounts of OD species (ca. 532 eV) probably formed on trace amounts of surface defects, while at 95 K D2O ice (533.5 eV) was the main surface species. On the contrary, a large signal of OD species was seen on the 300 K-Ar{sup +}-sputtered (reduced) surface, UO{sub 2-x}. This was concomitant with a rapid healing of surface defects as monitored by their U4f signal. Quantitative analysis of the OD signal with increasing temperature showed their disappearance by 550 K. The disappearance of these species while hydrogen molecules are still desorbing from the surface as monitored by TPD [S.D. Senanayake, H. Idriss, Surf. Sci. 563 (1-3) (2004) 135; S.D. Senanayake, R. Rousseau, D. Colegrave, H. Idriss, J. Nucl. Mater. 342 (2005) 179] is shedding light on the re-combinative desorption mechanism from dissociatively adsorbed water molecules on the surfaces of this defective metal oxide.},
doi = {10.1016/j.cattod.2006.07.040},
journal = {Catalysis Today},
number = ,
volume = 120,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}