First-Principle Study of Co-Adsorption Behavior of H2O and O2 on δ-Pu (100) Surface

Abstract

The surface corrosion of plutonium in air is mainly the result of the interaction with O2 and H2O in air. In this paper, the co-adsorption behavior of O2 and H2O on a δ-Pu (100) surface is studied by the first-principle method. Two different cases of preferential adsorption of H2O and O2 are considered, respectively. Bader charge analysis and adsorption energy analysis are carried out on all stable adsorption configurations, and the most stable adsorption configurations are found under the two conditions. The results of differential charge density analysis, the density of states analysis and Crystal Orbital Hamilton Populations (COHP) analysis show that the two molecules can promote each other’s adsorption behavior, which leads to the strength and stability of co-adsorption being far greater than that of single adsorption. In the co-adsorption configuration, O atoms preferentially interact with Pu atoms in the surface layer, and the essence is that the 2s and 2p orbitals of O overlap and hybridize with the 6p and 6d orbitals of Pu. H atoms mainly form O–H bonds with O atoms and hardly interact with Pu atoms on the surface layer.