Interaction of hydrogen with actinide dioxide (111) surfaces.

Autor: Pegg, James T., Shields, Ashley E., Storr, Mark T., Scanlon, David O., de Leeuw, Nora H.
Předmět:
Zdroj: Journal of Chemical Physics; 4/7/2019, Vol. 150 Issue 13, pN.PAG-N.PAG, 10p, 2 Diagrams, 6 Graphs
Abstrakt: The interaction of atomic and molecular hydrogen with actinide dioxide (AnO2, An = U, Np, Pu) (111) surfaces has been investigated by DFT+U, where noncollinear 3k antiferromagnetic behaviour and spin-orbit interactions are considered. The adsorption of atomic hydrogen forms a hydroxide group, coupled to the reduction of an actinide ion. The energy of atomic hydrogen adsorption on the UO2 (0.82 eV), NpO2 (−0.10 eV), and PuO2 (−1.25 eV) surfaces has been calculated. The dissociation of molecular hydrogen is not observed, shown to be due to kinetic rather than thermodynamic factors. As a barrier to the formation of a second hydroxyl group, an unusual charge distribution has been shown. This could be a limitation of a (1·1) unit cell method or an artefact of the systems. The recombination of hydrogen ions on the AnO2 (111) surfaces is favoured over hydroxide formation. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index