Ni Deposition on Yttria-Stabilized ZrO₂(111) Surfaces: A Density Functional Theory Study

Abstract

Nickel particles supported on yttria-stabilized zirconia (YSZ) play a significant role in the performance of solid oxide fuel cells (SOFC). We have investigated both pristine and doped ZrO₂ surfaces using spin polarized density functional theory (DFT) and also considering long-range dispersion forces. We have systematically studied Ni deposition on the bare ZrO₂(111) surface and on surfaces with two concentrations of Y, all at both high and low oxygen chemical potential. Among the several independent sites explored, the Ni adsorption preference is as follows: YSZ(111) without oxygen vacancy > YSZ(111) with oxygen vacancy > stoichiometric ZrO₂(111). For each surface, the adsorption site is similar: over the top oxygen. The evaluation of the geometric and electronic structure shows a mixing of Ni orbitals with surface atom orbitals. We have also investigated the influence of the yttrium atom on the Ni adsorption by considering up to 52 different configurations, which showed that Ni tends to adsorb away from the yttrium atom for any YSZ(111) surface, leading to a mixed electronic structure with enhanced charge transfer