First-principles study of the effect of dopants (Pd, Ni) on the formation and desorption of T(2)O from a Li(2)TiO(3) (001) surface

We investigated the effect of Pd and Ni dopants on the formation and desorption of tritiated water (T(2)O) molecules from the Li(2)TiO(3) (001) surface using first-principles calculations coupled with the climbing-image nudged elastic band method. We calculated the energy barriers for T(2)O production and desorption on the pure Li(2)TiO(3) surface to be 0.94 and 0.64 eV, respectively. The Pd and Ni dopants enhanced T(2)O formation by reducing the formation energy of O vacancies, and T(2)O 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 Li(2)TiO(3) surface. In addition, desorption of T(2)O from the doped Li(2)TiO(3) surface requires a relatively low energy (<0.50 eV). This theoretical study suggests that doping the Li(2)TiO(3) surface with metal atoms is an effective strategy for producing T(2)O molecules and is beneficial to T release.