First-principles explorations of the universal picture of oxide layer structure over metallic plutonium. (June 2019)

• Record Type: Journal Article
• Authors: Ao, Bingyun; Qiu, Ruizhi
• Is Part Of: Corrosion science. Volume 153(2019)
• Page Start: 236
• Page End: 248
• Publication Date: 2019-06
• Subjects: Plutonium oxides -- Cerium oxides -- Oxide layer -- Vacancy formation energy -- First-principles calculations; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2019.03.047
• Languages: English
• ISSNs: 0010-938X

Abstract

Graphical abstract: Highlights: The general trends of stability of stoichiometric and non-stoichiometric Pu oxides are firstly reported. A rigorous quantum definition of oxidation state is used to determine the atomic ratio of Pu 3+ /Pu 4+ in Pu oxides. The proposed ladder-like Pu oxide layer structure might be more reasonable than the sandwich-like structure. Abstract: The oxide layer structure over Pu is the central issue of Pu corrosion science; however, the widely discussed sandwich-like structure (Pu//Pu2 O3 //PuO2 ) might be just a phenomenological description. Here we perform first-principles calculations with the method verification on Ce oxides, the ideal analogues of Pu oxides, to establish a universal picture of Pu oxide layer structure. The results show that homogeneous Pu n O2 n -2 between PuO2 and Pu2 O3 are energetically more favorable than PuO2- x with ordered arrays of oxygen vacancies. Thus, a ladder-like oxide layer structure is proposed to improve a simple sandwich-like model of the Pu oxide layers.