Outstanding stability of Gd-doped UO2 against surface oxidation: First-principles study

Minjoon Hong, Hoje Chun, Choah Kwon, Byungchan Han

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1 Citation (Scopus)


An accurate understanding of structural integrity and chemical reactivity of UO2 disposed in deep underground sites is of importance. Owing to the specific condition of the site location, UO2 may have substantially different properties from the conventional prediction. In this study, we demonstrate that the oxidation resistivity of UO2 is considerably modified by gadolinium (Gd), which is the element of neutron absorber and a byproduct of nuclear decay of radioactive U-235. Using density functional theory calculations, we investigate how the oxidation mechanism of UO2 changes with Gd incorporation in U lattice. Our study indicates that Gd remarkably enhances the thermodynamic stability of pristine UO2 against surface oxidation via three underlying mechanisms: (i) weakens the chemical bonding of adsorbed oxygen atom (O) with U, (ii) reduces active sites (U) for oxygen adsorption, and (iii) suppresses the subsurface diffusion of adsorbed O delaying the growth of the oxide layers on the UO2. Electronic and lattice structure analyses for Gd-doped UO2 indicate that amount of charge transfer from U to O is critically reduced and the lattice of the UO2 surface is contracted. Our results provide useful information for understanding long-term stability and improving the structural integrity of UO2 through the chemical doping process.

Original languageEnglish
Article number152955
JournalApplied Surface Science
Publication statusPublished - 2022 Jul 1

Bibliographical note

Funding Information:
This paper was supported by “Ministry of the Interior and Safety” R&D program (no.20014778). This work was also supported by the Nuclear R&D Program of the National of Korea (NRF) grant funded by the Ministry of Science and ICT (NRF-2016M2B2B1945254). The National of Korea (NRF) grant funded by the Korean government (MSIT; No. 2017M2A8A5014754) also supported this research.

Publisher Copyright:
© 2022 Elsevier B.V.

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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