First-principles study of surface properties of PuO2: Effects of thickness and O-vacancy on surface stability and chemical activity

2012/03/13 by Bo Sun, Haifeng Liu, Haifeng Song +5 · 48 citations
Chemistry · Materials Science · Physics and Astronomy · #Analytical Chemistry (journal) #Chemical physics #Chemical stability #Chemistry #Computational chemistry #Crystallography #Density functional theory #Dipole #Electronic and Structural Properties of Oxides #Geometry #Materials science #Monolayer #Nanotechnology #Nuclear Materials and Properties #Oxide #Oxygen #Physical chemistry #Radioactive element chemistry and processing #Stoichiometry #Surface (topology) #Surface energy #Vacancy defect #Work function #cond-mat.mtrl-sci

paper · pdf · doi:10.1016/j.jnucmat.2012.02.029

published in Journal of Nuclear Materials 426(1-3), 139-147 (Elsevier BV) · 9 JNM pages, 7 figures

openalex publication_date 2012/03/13 · arxiv created 2012/08/18 · arxiv updated 2012/08/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

The (111), (110), and (001) surfaces properties of PuO2 are studied by using density-functional theory+U method. The total-energy static calculations determine the relative order of stability for low-index PuO2 surfaces, namely, O-terminated (111) > (110) > defective (001) > polar (001). The effect of thickness is shown to modestly modulate the surface stability and chemical activity of the (110) surface. The high work function of 6.19 eV indicates the chemical inertia of the most stable (111) surface, and the surface O-vacancy with concentration C_V=25% can efficiently lower the work function to 4.35 eV, which is a crucial indicator of the difference in the surface chemical activities between PuO2 and α-Pu2O3. For the polar (001) surface, 50% on-surface O-vacancy can effectively quench the dipole moment and stabilize the surface structure, where the residual surface oxygen atoms are arranged in a zigzag manner along the <100> direction. We also investigate the relative stability of PuO2 surfaces in an oxygen environment. Under oxygen-rich conditions, the stoichiometric O-terminated (111) is found to be the most stable surface. Whereas under O-reducing conditions, the on-surface O-vacancy of C_V = 1/9 is stable, and for high reducing conditions, the (111) surface with nearly one monolayer subsurface oxygen removed (C_V = 8/9) becomes most stable.

Citations

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• Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study
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• Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set
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