Using in situ X-ray absorption spectroscopy to study the local structure and oxygen ion conduction mechanism in (La0.6Sr0.4)(Co0.2Fe0.8)O3−δ

2012 ◽  
Vol 192 ◽  
pp. 38-46 ◽  
Author(s):  
Takanori Itoh ◽  
Masanobu Nakayama
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Conduction Mechanism ◽  
Ion Conduction ◽  
X Ray ◽  
Oxygen Ion ◽  
X Ray Absorption ◽  
Ion Conduction Mechanism

Oxygen Partial Pressure Dependence of In Situ X-Ray Absorption Spectroscopy at Co and Fe K-Edge for (La0.6Sr0.4)(Co0.2Fe0.8)O3–δ

2012 ◽  
Vol 9 (3) ◽  
Author(s):  
Takanori Itoh ◽  
Saori Shirasaki ◽  
Hironori Ofuchi ◽  
Sayaka Hirayama ◽  
Tetsuo Honma ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Oxygen Vacancies ◽  
Ion Conductivity ◽  
Ion Conduction ◽  
Edge Structure ◽  
X Ray ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion ◽  
X Ray Absorption

(La0.6Sr0.4)(Co0.2Fe0.8)O3–δ (LSCF) has been promised as a cathode material of solid oxide fuel cells at intermediate temperatures. Despite the many previous studies of LSCF that have been reported, the role of Co and Fe atoms in the oxygen ion conduction is still unclear. In this work, we aimed at presenting each valence, oxygen chemical diffusion coefficient (Dchem) and activation energy (Ea) related to Co and Fe in LSCF by in situ X-ray absorption spectroscopy (XAS) at high temperatures and during reduction. For quantitative analysis of X-ray absorption near edge structure (XANES) spectroscopy, these results indicated that the Co valence decreased more easily than the Fe valence. On the other hand, from relaxation plots of the Co and Fe valence during reduction, the values of Dchem and Ea related to Co and Fe were nearly equal. Considering equations showing the oxygen ion conductivity, these results would indicate that oxygen ion conductivity was contributed by Co with more oxygen vacancies rather than Fe. According to these results, a structural model with and without oxygen vacancies and the oxygen ion conduction mechanism of LSCF was speculated, that is, we found that oxygen ion conductivity was more closely related to Co than Fe in LSCF by direct observations of in situ XAS.

Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

2019 ◽  
Author(s):  
Jisue Moon ◽  
Carter Abney ◽  
Dmitriy Dolzhnikov ◽  
James M. Kurley ◽  
Kevin A. Beyer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chloride Salt ◽  
X Ray ◽  
Molten Chloride ◽  
Stable Species ◽  
Higher Temperature ◽  
Cr Concentration ◽  
X Ray Absorption

The local structure of dilute CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800<sup>o</sup>C. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions at higher temperature (>700<sup>o</sup>C) prevented confirmation of the local structure.

Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

2019 ◽  
Author(s):  
Jisue Moon ◽  
Carter Abney ◽  
Dmitriy Dolzhnikov ◽  
James M. Kurley ◽  
Kevin A. Beyer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chloride Salt ◽  
X Ray ◽  
Molten Chloride ◽  
Stable Species ◽  
Higher Temperature ◽  
Cr Concentration ◽  
X Ray Absorption

The local structure of dilute CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800<sup>o</sup>C. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions at higher temperature (>700<sup>o</sup>C) prevented confirmation of the local structure.

Monitoring a CuO gas sensor at work: an advanced in situ X-ray absorption spectroscopy study

2015 ◽  
Vol 17 (28) ◽  
pp. 18761-18767 ◽  
Author(s):  
D. P. Volanti ◽  
A. A. Felix ◽  
P. H. Suman ◽  
E. Longo ◽  
J. A. Varela ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Absorption Spectroscopy ◽  
Working Conditions ◽  
Local Structure ◽  
Spectroscopy Study ◽  
Electrical Measurements ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

X-ray absorption near edge structure (XANES) and electrical measurements were used to elucidate the local structure and electronic changes of copper(ii) oxide (CuO) nanostructures under working conditions.

Local structure of LiNi0.5Mn0.5O2 cathode material probed by in situ x-ray absorption spectroscopy

2006 ◽  
Vol 99 (6) ◽  
pp. 063701 ◽  
Author(s):  
Aniruddha Deb ◽  
Uwe Bergmann ◽  
Stephen P. Cramer ◽  
Elton J. Cairns
Keyword(s):  
Cathode Material ◽  
Absorption Spectroscopy ◽  
Local Structure ◽  
X Ray ◽  
Lini0.5Mn0.5O2 Cathode Material ◽  
X Ray Absorption

Revealing the structural transformation of rutile RuO2via in situ X-ray absorption spectroscopy during the oxygen evolution reaction

2019 ◽  
Vol 48 (21) ◽  
pp. 7122-7129 ◽  
Author(s):  
Chia-Jui Chang ◽  
You-Chiuan Chu ◽  
Hao-Yu Yan ◽  
Yen-Fa Liao ◽  
Hao Ming Chen
Keyword(s):  
Oxygen Evolution ◽  
Structural Transformation ◽  
Absorption Spectroscopy ◽  
Oxygen Evolution Reaction ◽  
The State ◽  
X Ray ◽  
Alkaline Conditions ◽  
X Ray Absorption ◽  
State Of Art

The state-of-art RuO2 catalyst for the oxygen evolution reaction (OER) is measured by using in situ X-ray absorption spectroscopy (XAS) to elucidate the structural transformation during catalyzing the reaction in acidic and alkaline conditions.

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