Abstract
The corrosion and oxidation of actinide metals, leading to the formation of metal-oxide surface layers with the catalytic evolution of hydrogen, impacts the management of nuclear materials. Here, the interaction of hydrogen with actinide dioxide (AnO2, An = U, Np, or Pu) (011) surfaces by Hubbard corrected density functional theory (PBEsol+U) has been studied, including spin-orbit interactions and non-collinear 3k anti-ferromagnetic behavior. The actinide dioxides crystalize in the fluorite-type structure, and although the (111) surface dominates the crystal morphology, the (011) surface energetics may lead to more significant interaction with hydrogen. The dissociative adsorption of hydrogen on the UO2 (0.44 eV), NpO2 (-0.47 eV), and PuO2 (-1.71 eV) (011) surfaces has been calculated. It is found that hydrogen dissociates on the PuO2 (011) surface; however, UO2 (011) and NpO2 (011) surfaces are relatively inert. Recombination of hydrogen ions is likely to occur on the UO2 (011) and NpO2 (011) surfaces, whereas hydroxide formation is shown to occur on the PuO2 (011) surface, which distorts the surface structure.
| Original language | English |
|---|---|
| Article number | 014705 |
| Journal | Journal of Chemical Physics |
| Volume | 153 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 7 2020 |
Funding
Notice: This manuscript was co-authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This research was supported by the UK Engineering and Physical Science Research Council (EPSRC) (Grant Nos. EP/G036675 and EP/K016288) and the Atomic Weapons Establishment (AWE). J.T.P. thanks Ornella Romeo for her help and kindness. A.E.S. acknowledges the United States Department of Homeland Security (DHS), Domestic Nuclear Detection Office (DNDO), National Technical Nuclear Forensics Center (NTNFC), for a Postdoctoral Research Fellowship. N.H.L. thanks the Royal Society for an Industry Fellowship and AWE for a William Penney Fellowship. This work made use of the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk), via our membership of the UK’s HEC Materials Chemistry Consortium, which is funded by EPSRC (Grant No. EP/L000202).
| Funders | Funder number |
|---|---|
| National Technical Nuclear Forensics Center | |
| U.S. Department of Energy | |
| U.S. Department of Homeland Security | |
| Design History Society | |
| Domestic Nuclear Detection Office | |
| Engineering and Physical Sciences Research Council | EP/G036675, EP/K016288 |
| Royal Society | EP/L000202 |
| Atomic Weapons Establishment |