First-principles study of the effect of dopants (Pd, Ni) on the formation and desorption of T2O from a Li2TiO3 (001) surface

Abstract

We investigated the effect of Pd and Ni dopants on the formation and desorption of tritiated water (T₂O) molecules from the Li₂TiO₃ (001) surface using first-principles calculations coupled with the climbing-image nudged elastic band method. We calculated the energy barriers for T₂O production and desorption on the pure Li₂TiO₃ surface to be 0.94 and 0.64 eV, respectively. The Pd and Ni dopants enhanced T₂O formation by reducing the formation energy of O vacancies, and T₂O generated spontaneously on the dopant surface. Moreover, we found that dopant atoms affect the charge transfer of neighboring atoms, which leads to orbital hybridization and the generation of a chemical bond between the O and T on the doped Li₂TiO₃ surface. In addition, desorption of T₂O from the doped Li₂TiO₃ surface requires a relatively low energy (<0.50 eV). This theoretical study suggests that doping the Li₂TiO₃ surface with metal atoms is an effective strategy for producing T₂O molecules and is beneficial to T release.