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.

scholarly journals A compact furnace for in situ X-ray absorption spectroscopy: design, fabrication and study of cationic oxidation states in Pr6O11 and NiO

2021 ◽  
Vol 28 (2) ◽  
pp. 455-460
Author(s):  
Suchinda Sattayaporn ◽  
Somboonsup Rodporn ◽  
Pinit Kidkhunthod ◽  
Narong Chanlek ◽  
Chutarat Yonchai ◽  
...  
Keyword(s):  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Heating Temperature ◽  
Reduction Process ◽  
Oxidation States ◽  
Quartz Tube ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

A well designed compact furnace has been designed for in situ X-ray absorption spectroscopy (XAS). It enables various heat ramps from 300 K to 1473 K. The furnace consists of heaters, a quartz tube, a circulated refrigerator and a power controller. It can generate ohmic heating via an induction process with tantalum filaments. The maximum heating rate exceeds 20 K min−1. A quartz tube with gas feedthroughs allows the mixing of gases and adjustment of the flow rate. The use of this compact furnace allows in situ XAS investigations to be carried out in transmission or fluorescence modes under controlled temperature and atmosphere. Moreover, the furnace is compact, light and well compatible to XAS. The furnace was used to study cationic oxidation states in Pr6O11 and NiO compounds under elevated temperature and reduced atmosphere using the in situ X-ray absorption near-edge structure (XANES) technique at beamline 5.2 SUT-NANOTEC-SLRI of the Synchrotron Light Research Institute, Thailand. At room temperature, Pr6O11 contains a mixture of Pr3+ and Pr4+ cations, resulting in an average oxidation state of +3.67. In situ XANES spectra of Pr (L 3-edge) show that the oxidation state of Pr4+ cations was totally reduced to +3.00 at 1273 K under H2 atmosphere. Considering NiO, Ni2+ species were present under ambient conditions. At 573 K, the reduction process of Ni2+ occurred. The Ni0/Ni2+ ratio increased linearly with respect to the heating temperature. Finally, the reduction process of Ni2+ was completely finished at 770 K.

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.

scholarly journals In situ X-ray absorption near edge structure studies and charge transfer kinetics of Na6[V10O28] electrodes

2017 ◽  
Vol 19 (4) ◽  
pp. 3358-3365 ◽  
Author(s):  
Han-Yi Chen ◽  
Jochen Friedl ◽  
Chun-Jern Pan ◽  
Ali Haider ◽  
Rami Al-Oweini ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Absorption Spectroscopy ◽  
Edge Structure ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Kinetics Of

The electron transfer of Na6[V10O28] was investigated byin situV K-edge X-ray absorption spectroscopy and chronoamperometric experiments for the first time.

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.

Unveiling the Complex Redox Reactions of SnO2 in Li-Ion Batteries Using Operando X-ray Photoelectron Spectroscopy and In Situ X-ray Absorption Spectroscopy

2021 ◽  
Vol 13 (2) ◽  
pp. 2547-2557
Author(s):  
Marta Mirolo ◽  
Xiaohan Wu ◽  
Carlos A. F. Vaz ◽  
Petr Novák ◽  
Mario El Kazzi
Keyword(s):  
Absorption Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Redox Reactions ◽  
Li Ion Batteries ◽  
X Ray ◽  
Li Ion ◽  
X Ray Absorption

scholarly journals Resolving the Evolution of Atomic Layer-Deposited Thin-Film Growth by Continuous In Situ X-Ray Absorption Spectroscopy

2021 ◽  
Author(s):  
Xiaohui Qu ◽  
Danhua Yan ◽  
Ruoshui Li ◽  
Jiajie Cen ◽  
Chenyu Zhou ◽  
...  
Keyword(s):  
Thin Film ◽  
Absorption Spectroscopy ◽  
Film Growth ◽  
Atomic Layer ◽  
Thin Film Growth ◽  
X Ray ◽  
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.

Simple flow through reaction cells for in situ transmission and fluorescence x-ray-absorption spectroscopy of heterogeneous catalysts

2006 ◽  
Vol 77 (2) ◽  
pp. 023105 ◽  
Author(s):  
Simon R. Bare ◽  
George E. Mickelson ◽  
Frank S. Modica ◽  
Andrzej Z. Ringwelski ◽  
N. Yang
Keyword(s):  
Absorption Spectroscopy ◽  
Heterogeneous Catalysts ◽  
X Ray ◽  
Flow Through ◽  
X Ray Absorption ◽  
Simple Flow

scholarly journals Unraveling the Structure of Mn-Promoted Co/TiO2 Fischer-Tropsch Catalysts by In Situ X-Ray Absorption Spectroscopy

2007 ◽  
Author(s):  
Didier Grandjean ◽  
Fernando Morales ◽  
Ad Mens ◽  
Frank M. F. de Groot ◽  
Bert M. Weckhuysen
Keyword(s):  
Absorption Spectroscopy ◽  
Fischer Tropsch ◽  
X Ray ◽  
X Ray Absorption
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