Related Experiment Video
Updated: Feb 16, 2026
11:25
In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries
Published on: November 10, 2014
16.3K
Phase Transformations in the CeO2-Sm2O3 System: A Multiscale Powder Diffraction Investigation
Mauro Coduri1,2,3, Paolo Masala1, Mattia Allieta1
1Dipartimento di Chimica, Università degli Studi di Milano , Via C. Golgi 19, I-20133 Milano, Italy.
Inorganic Chemistry
|December 28, 2017
Summary
The structure of samarium-doped ceria (CeO2-Sm2O3) transforms from fluorite to cubic and then monoclinic phases. Nanodomain growth, not phase separation, drives this transformation, impacting oxygen vacancy ordering.
Area of Science:
- Materials Science
- Solid State Chemistry
- Nanotechnology
Background:
- Ceria (CeO2) is a key material for solid oxide fuel cell electrolytes.
- Doping ceria with rare earth oxides like samarium oxide (Sm2O3) enhances ionic conductivity.
- Understanding the structural evolution in doped ceria is crucial for optimizing its performance.
Purpose of the Study:
- To investigate the structural transformations in the CeO2-Sm2O3 system.
- To elucidate the local, mesoscopic, and average structure evolution with Sm doping.
- To understand the mechanism of phase transitions and its impact on oxygen vacancy ordering.
Main Methods:
- High-resolution synchrotron powder diffraction.
- Pair distribution function (PDF) analysis.
- Combined analysis of local and average structure.
Main Results:
- CeO2 undergoes two phase transformations with Sm doping: fluorite to cubic (C-type) and then to monoclinic (B-type).
- A miscibility gap exists between C-type and B-type phases, leading to long-range phase separation.
- No miscibility gap was observed between fluorite and C-type phases; transformation occurs via C-type nanodomain growth within the fluorite matrix.
- Oxygen vacancy ordering was observed as a consequence of this nanostructure formation, potentially hindering fuel cell applications.
Conclusions:
- The structural evolution in CeO2-Sm2O3 is driven by nanodomain growth rather than long-range phase separation for the fluorite to C-type transition.
- Oxygen vacancy ordering induced by nanostructuring can negatively affect the performance of doped ceria electrolytes.
- These findings provide insights into structure-property relationships in doped ceria systems relevant to fuel cell technology.
More Related Videos
09:16X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects
Published on: June 8, 2016
16.8K
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
9.0K
Related Concept Videos
02:18Interference and Diffraction
52.6K
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
52.6K
01:33Bacterial Transformation
60.4K
In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.
Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
60.4K
01:10X-ray Diffraction of Biological Samples
4.9K
X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal...
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal...
4.9K
02:33Phase Transitions: Sublimation and Deposition
20.4K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
20.4K
02:39Phase Diagrams
50.6K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
50.6K
02:31Phase Transitions
23.3K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.3K