Ceria-Based Mixed Oxides - Beautiful Structures.

Abstract

This minireview intends to summarize the knowledge about the microstructure of the ceria based mixed oxides Ce1‐xLnxO2‐(x/2). During the years, idea about the Ce1‐xLnxO2‐(x/2) structure has been changed and evolved in to a complicated, beautiful but realistic model. Based on the literature data, the mechanism of F → C structure transformation for Ce1−xLnxO2−(x/2), with increasing of Ln3+‐ions concentration, has been proposed. Traced the way to describe the beautiful structure of Ce1‐xLnxO2‐(x/2), depending on the phase composition of the mixed oxide, could be very helpful for the design of new materials with interesting properties and potential technological applications.

Oxygen Vacancy Distribution in Yttrium-Doped Ceria from 89Y–89Y Correlations via Dynamic Nuclear Polarization Solid-State NMR

“…For instance, based on diffraction data, the existence of nanodomains of Y 2 O 3 within CeO 2 has been proposed 6 and is supported by other experimental findings. 7 − 10 On the other hand, nuclear magnetic resonance (NMR) data suggested the preferred formation of yttrium pairs, but the absence of larger clusters, 11 in line with a structural model proposed by Małecka et al 12 , 13 for Yb 3+ -doped ceria. Efforts to obtain a full understanding of the structure need to focus on connecting long-range structural properties with an understanding at the atomic scale.…”

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

“…The superior catalytic capability of CeO 2 are straightly linked to the reversible redox pair Ce 3+ /C 4+ and to its surface acid basic properties (Trovarelli, 1996). Moreover, when nanostructured, or in its doped form, this oxide is characterized by a large number of surface defects, primarily oxygen vacancies (Małecka, 2016; Trovarelli and Llorca, 2017). The presence of these defects on the surface often alters dramatically the adsorption and subsequent reactions of various adsorbates on the support and on metal particles.…”

Phase Transformations in the CeO2–Sm2O3 System: A Multiscale Powder Diffraction Investigation

“…From the technological point of view, the interest comes from their application as electrolytes in solid oxide fuel cells (SOFCs) because of their high ionic conductivity displayed at high and intermediate temperatures . Despite their apparent simplicity, fluorite structures like CeO 2 are known to accommodate a high concentration of lattice defects, thus being also a reference system for modeling disorder. − This aspect is particularly important for doped ceria electrolytes, where doping of ceria with lower valent cations creates oxygen vacancies through which oxygen ions can diffuse via a thermally activated process. As ionic conductivity has inverse dependence on the activation energy needed by oxygen ions to migrate through the lattice, the accurate description of the crystal structure, from the local to the average crystal environment, is of primary importance.…”