A First-Principles Modeling of Ni Interactions on CeO₂−ZrO₂Mixed Oxide Solid Solutions

Abstract

We performed DFT+U quantum period calculations to study the characteristics of Ni interactions on/in CeO2−ZrO2 mixed oxide solid solutions. We analyzed the energetics of Ni adsorption and insertion on/in different surface and subsurface sites of the Ce0.25Zr0.75O2(111) slab, and also the changes in its atomic and electronic structures. The most stable interaction corresponds to a single Ni atom adsorbed on the O−O bridge site, where the nearest-neighbor metal atom is the Zr. Our calculations also show that Ni can form small clusters on the Ce0.75Zr0.25O2(111) surface; which also locate around the Zr dopant. Due to Ni interactions, surface and inner layers oxygen anions experience important modifications in their geometric positions and the Ni atom deposition results in the partial occupation of 7-coordinated Ce(4f) states.