�ber anomale Mischkristalle im Bereiche des Fluoritgittertyps

Bräuer, G.; Gradinger, H.

doi:10.1007/bf00592066

Cited by 25 publications

(2 citation statements)

References 5 publications

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“…38 Particular attention has been given to the data reported for systems after reaching the thermodynamic equilibrium following treatment at high temperature, for uses in SOFCs. In samples calcined at 1400 °C, complete miscibility with CeO 2 have been reported for M = Y, Sm, Eu, Gd, and Dy, 38,83,84 while maximum solubility around 25 − 50 mol % are reported for M = La, Pr, Nd, and Yb. 83,85,86 This is in agreement with the ionic radius of these elements in the 3+ oxidation state, 22 with the first group having the best correspondence with the matching radius reported by Kim to minimize the elastic energy induced by the introduction of the kth dopant.…”

Section: Solid Solutions Containing Ceomentioning

confidence: 99%

Fundamentals and Catalytic Applications of CeO₂-Based Materials

et al. 2016

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Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40(th) anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are deepening our understanding of these materials, helping us to predict their behavior and application potential. This review has a wide view on all those aspects related to ceria which promise to produce an important impact on our life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.

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Section: Solid Solutions Containing Ceomentioning

confidence: 99%

Fundamentals and Catalytic Applications of CeO₂-Based Materials

et al. 2016

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“…60,61 For Y, Gd and Sm doped ceria, solubility of at least x = 0.3 up to complete miscibility is reported. 57,62 The lattice parameter of doped ceria depends on the ionic radius of the dopant. For Ce 0.8 RE 0.2 O 1.9 , the lattice parameter changes linearly with the dopant radius obeying Vegard's law.…”

Section: Introductionmentioning

confidence: 99%

Understanding the ionic conductivity maximum in doped ceria: trapping and blocking

Koettgen

Grieshammer

Hein

et al. 2018

Phys. Chem. Chem. Phys.

139

178

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Materials with high oxygen ion conductivity and low electronic conductivity are required for electrolytes in solid oxide fuel cells (SOFC) and high-temperature electrolysis (SOEC). A potential candidate for the electrolytes, which separate oxidation and reduction processes, is rare-earth doped ceria. The prediction of the ionic conductivity of the electrolytes and a better understanding of the underlying atomistic mechanisms provide an important contribution to the future of sustainable and efficient energy conversion and storage. The central aim of this paper is the detailed investigation of the relationship between defect interactions at the microscopic level and the macroscopic oxygen ion conductivity in the bulk of doped ceria. By combining ab initio density functional theory (DFT) with Kinetic Monte Carlo (KMC) simulations, the oxygen ion conductivity is predicted as a function of the doping concentration. Migration barriers are analyzed for energy contributions, which are caused by the interactions of dopants and vacancies with the migrating oxygen vacancy. We clearly distinguish between energy contributions that are either uniform for forward and backward jumps or favor one migration direction over the reverse direction. If the presence of a dopant changes the migration energy identically for forward and backward jumps, the resulting energy contribution is referred to as blocking. If the change in migration energy due to doping is different for forward and backward jumps of a specific ionic configuration, the resulting energy contributions are referred to as trapping. The influence of both effects on the ionic conductivity is analyzed: blocking determines the dopant fraction where the ionic conductivity exhibits the maximum. Trapping limits the maximum ionic conductivity value. In this way, a deeper understanding of the underlying mechanisms determining the influence of dopants on the ionic conductivity is obtained and the ionic conductivity is predicted more accurately. The detailed results and insights obtained here for doped ceria can be generalized and applied to other ion conductors that are important for SOFCs and SOECs as well as solid state batteries.

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