Oxygen vacancy ordering induced displacements of cations in yttria-stabilized zirconia

Abstract

Using scanning transmission electron microscopy, we report direct observation of oxygen vacancy ordering induced atomic displacements of the cation sub-lattice in yttria-stabilized zirconia (YSZ). We find that the cation lattice adopts a zigzag configuration along the [100] direction with alternately narrow and wide lattice spacings equivalent of 0.85 and 1.15 times of the (200) inter-planar distance of the cubic YSZ. Using atomistic simulations, we show that the cation displacements are induced by the alternate presence of oxygen vacancies at the (1/4, 1/4, 1/4) and (1/4, 3/4, 1/4) sites of the unit cells in the [001] direction. The results demonstrate that significant enrichment of yttrium atoms can occur within individual YSZ grains in addition to the typical surface or grain boundary segregation of dopant atoms.

Formation of an Anti-Core–Shell Structure in Layered Oxide Cathodes for Li-Ion Batteries

“…The reduced TM cations can easily migrate onto the Li sites of the layered phase, 31 increasing the disordering between TM and Li cations and inducing rock-salt features in the layered phase, as shown in Figure 3d−f. When an overly high amount of vacancies stays in the surface layered phase during the outward diffusion of oxygen, the merging of the oxygen vacancies damages the lattice frame of oxygen 25,49 and leads to more significant structural imperfections than interlayer mixing between Li and TM cations: the collapse of the oxygen frame of the layered structure and the displacement of the Li-site TM cations. Accordingly, a high concentration of stacking faults develops in the layered structure, as shown in Figure 3g−i.…”

Structural properties of mixed conductor Ba1−xGd1−yLax+yCo2O6−δ

“…When a new oxygen vacancy is formed, the radius of the vacancy is smaller than for the host oxide ion, 18 but it still causes coulombic repulsion between the surrounding cations. 19 This repulsion can be counteracted by an inward attraction felt by the surrounding oxide ions towards the oxygen vacancy (Fig. 15).…”

Unique κ-Ce2Zr2O8 Superstructure Promoting the NOx Adsorption-Selective Catalytic Reduction (AdSCR) Performance of the WO3/CeZrOx Catalyst

“…When oxygen vacancies are formed, the adjacent cations would repel each other owing to the Coulomb interaction, causing a change in lattice spacing. 50 Herein, the lattice structure of CeO 2 has been changed and rich oxygen vacancies were formed due to the formation of the κ-Ce 2 Zr 2 O 8 structure. Additionally, O 2 could be easily adsorbed on such oxygen vacancies and form active oxygen atoms O*; 51 therefore, the CZ-h and W/CZ-h catalysts showed higher oxygen capture capacity than CZ-a and W/CZ-a references, respectively, which can be verified by the O 2 -TPD results in Figure 2b.…”