Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Structural investigations of La0.6Sr0.4FeO3-δ under reducing conditions: kinetic and thermodynamic limitations for phase transformations and iron exsolution phenomena

Journal Article · · RSC Advances
DOI:https://doi.org/10.1039/c7ra12309d· OSTI ID:1485071
 [1];  [2];  [2];  [3];  [1];  [1];  [4];  [4];  [5];  [2];  [1];  [1]
  1. University of Innsbruck (Austria)
  2. Technical University Berlin (Germany)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Nagoya University, Furo-cho, Chikusa-ku (Japan)
  5. RIKEN SPring-8 Center, Sayo (Japan)
+ Show Author Affiliations

The crystal structure changes and iron exsolution behavior of a series of oxygen-deficient lanthanum strontium ferrite (La0.6Sr0.4FeO3-δ, LSF) samples under various inert and reducing conditions up to a maximum temperature of 873 K have been investigated to understand the role of oxygen and iron deficiencies in both processes. Iron exsolution occurs in reductive environments at higher temperatures, leading to the formation of Fe rods or particles at the surface. Utilizing multiple ex situ and in situ methods (in situ X-ray diffraction (XRD), in situ thermogravimetric analysis (TGA), and scanning X-ray absorption near-edge spectroscopy (XANES)), the thermodynamic and kinetic limitations are accordingly assessed. Prior to the iron exsolution, the perovskite undergoes a nonlinear shift of the diffraction peaks to smaller 2θ angles, which can be attributed to a rhombohedral-to-cubic (R$$\overline{3}$$c to Pm$$\overline{3}$$m) structural transition. In reducing atmospheres, the cubic structure is stabilized upon cooling to room temperature, whereas the transition is suppressed under oxidizing conditions. This suggests that an accumulation of oxygen vacancies in the lattice stabilize the cubic phase. The exsolution itself is shown to exhibit a diffusion-limited Avrami-like behavior, where the transport of iron to the Fe-depleted surface-near region is the rate-limiting step.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1485071
Journal Information:
RSC Advances, Journal Name: RSC Advances Journal Issue: 6 Vol. 8; ISSN 2046-2069; ISSN RSCACL
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English

References (32)

Enhancing Electrochemical Water-Splitting Kinetics by Polarization-Driven Formation of Near-Surface Iron(0): An In Situ XPS Study on Perovskite-Type Electrodes journal December 2014
Enhancing Electrochemical Water-Splitting Kinetics by Polarization-Driven Formation of Near-Surface Iron(0): An In Situ XPS Study on Perovskite-Type Electrodes journal December 2014
Rhodium-Catalyzed Methanation and Methane Steam Reforming Reactions on Rhodium-Perovskite Systems: Metal-Support Interaction journal May 2016
CO/CO 2 Study of High Performance La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3- δ Reversible SOFC Electrodes journal September 2015
The Crystal Chemistry and Physical Properties of the Triple Layer Perovskite Intergrowths LaSr3Fe3O10-δ and LaSr3(Fe3-xAlx)O10-δ journal March 1993
The Effect of Oxygen Stoichiometry on Phase Relations and Structure in the System La1-xSrxFeO3-δ (0 ≤ x ≤ 1, 0 ≤ δ ≤ 0.5) journal March 1994
Die Strukturen von Verbindungen ABO3 „Schwesterstrukturen.“ journal September 1943
Kinetics and mechanisms of exsolution journal January 1970
Ni doped La 0.6 Sr 0.4 FeO 3- δ symmetrical electrode for solid oxide fuel cells journal August 2016
Exsolution of Fe and SrO Nanorods and Nanoparticles from Lanthanum Strontium Ferrite La 0.6 Sr 0.4 FeO 3−δ Materials by Hydrogen Reduction journal September 2015
La 0.8 Sr 0.2 FeO 3−δ as Fuel Electrode for Solid Oxide Reversible Cells Using LaGaO 3 -Based Oxide Electrolyte journal May 2016
Structural and Chemical Evolution of the SOFC Anode La 0.30 Sr 0.70 Fe 0.70 Cr 0.30 O 3−δ upon Reduction and Oxidation: An in Situ Neutron Diffraction Study journal May 2010
Hollow Nanocrystals through the Nanoscale Kirkendall Effect journal December 2012
Anisotropic and Nonlinear Thermal and Chemical Expansion of La 1– x Sr x FeO 3−δ ( x = 0.3, 0.4, 0.5) Perovskite Materials journal August 2013
The Nanoscale Kirkendall Effect in Pd-Based Intermetallic Phases journal July 2014
In situ growth of nanoparticles through control of non-stoichiometry journal October 2013
Advanced anodes for high-temperature fuel cells journal January 2004
A dense La(Sr)Fe(Mn)O 3−δ nano-film anode for intermediate-temperature solid oxide fuel cells journal January 2015
Investigation of In-doped BaFeO 3−δ perovskite-type oxygen permeable membranes journal January 2015
Surface chemistry of pure tetragonal ZrO 2 and gas-phase dependence of the tetragonal-to-monoclinic ZrO 2 transformation journal January 2017
Novel cobalt-free BaFe 1−x Gd x O 3−δ perovskite membranes for oxygen separation journal January 2016
Compact low power infrared tube furnace for in situ X-ray powder diffraction journal January 2017
The lattice expansion of iron
  • Basinski, Zbigniew Stanislaw; Hume-Rothery, William; Sutton, A. L.
  • Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, Vol. 229, Issue 1179, p. 459-467 https://doi.org/10.1098/rspa.1955.0102
journal May 1955
Crystal structure, magnetic properties, and Mössbauer studies of La 0.6 Sr 0.4 FeO 3 − δ prepared by quenching in different atmospheres journal November 2002
Effective ionic radii in oxides and fluorides journal May 1969
Crystal Structure and Thermal Expansion of La1−xSrxFeO3−δ Materials journal October 2004
Advanced anodes for high-temperature fuel cells book October 2010
La(Sr)Fe(Mn)O3 Thin Film Anode for Improving Power Generating Property with Enhancing Electric Conductivity and Oxidation Activity journal October 2013
Iron Exsolution Phenomena in Lanthanum Strontium Ferrite SOFC Anodes journal May 2017
Solid Oxide Fuel Cell Fabricated Using All-Perovskite Materials journal January 2006
New Insight into Hydrogen Oxidation Reaction on La 0.3 Sr 0.7 Fe 0.7 Cr 0.3 O 3-δ Perovskite as a Solid Oxide Fuel Cell Anode journal January 2017
Effects of Firing and Reduction Conditions on Swelling and Iron Whisker Formation during the Reduction of Iron Oxide Compact journal January 2011

Cited By (2)

Crystallographic and electronic evolution of lanthanum strontium ferrite (La 0.6 Sr 0.4 FeO 3−δ ) thin film and bulk model systems during iron exsolution journal January 2019
Modifying the Surface Structure of Perovskite-Based Catalysts by Nanoparticle Exsolution journal March 2020

Similar Records

Crystallographic and electronic evolution of lanthanum strontium ferrite (La0.6Sr0.4FeO3-δ) thin film and bulk model systems during iron exsolution
Journal Article · Mon Jan 14 23:00:00 EST 2019 · Physical Chemistry Chemical Physics. PCCP · OSTI ID:1656498
Exsolution Synthesis of Nanocomposite Perovskites with Tunable Electrical and Magnetic Properties
Journal Article · Wed Nov 17 23:00:00 EST 2021 · Advanced Functional Materials · OSTI ID:1844587
Tuning Point Defects by Elastic Strain Modulates Nanoparticle Exsolution on Perovskite Oxides
Journal Article · Tue Jun 15 00:00:00 EDT 2021 · Chemistry of Materials · OSTI ID:1807942

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY