First-Principles Study of Hydrogen Behaviors in $Î±$-Pu$_{2}$O$_{3}$

Le Zhang; Bo Sun; Qili Zhang; Haifeng Liu; Kezhao Liu; Haifeng Song

paper

First-Principles Study of Hydrogen Behaviors in $I^\pm$ -Pu $_{2}$ O $_{3}$

arXiv:1906.06712

Abstract

The in-depth understanding of hydrogen permeation through plutonium-oxide overlayers is the prerequisite to evaluate the complex hydriding induction period of Pu. In this work, the incorporation, diffusion and dissolution of hydrogen in $I^\pm$ -Pu $_{2}$ O $_{3}$ are investigated by the first-principles calculations and $ab initio$ thermodynamic method based on DFT+U and DFT-D3 schemes. Our study reveals that the hydrogen incorporation is endothermic and the separated H atoms prefer to recombine as H $_{2}$ molecules rather than reacting with $I^\pm$ -Pu $_{2}$ O $_{3}$ . The H and H $_{2}$ diffusion are both feasible, generally, H will recombine first as H $_{2}$ and then migrate. Both pressure P $_{H 2}$ and temperature can promote the hydrogen dissolution in $I^\pm$ -Pu $_{2}$ O $_{3}$ . The single H $_{2}$ molecule incorporation and (H+H $_{2}$ ) mixed dissolution will successively appear when increasing P $_{H 2}$ . Compared to PuO $_{2}$ , this work indicates that Pu sesquioxide is hardly reduced by hydrogen, but the porous $I^\pm$ -Pu $_{2}$ O $_{3}$ facilitates hydrogen transport in Pu oxide layers. We presents the microscopic picture of hydrogen behaviors in the defect-free $I^\pm$ -Pu $_{2}$ O $_{3}$ , which could shed some light on the study of the hydriding induction period of Pu.

19 pages, 6 figures

First-Principles Study of Hydrogen Behaviors in I^±-Pu2​O3​

Abstract

First-Principles Study of Hydrogen Behaviors in $I^\pm$ -Pu $_{2}$ O $_{3}$