Oxygen nonstoichiometry, chemical expansion, mixed conductivity, and anodic behavior of Mo-substituted Sr3Fe2O7-δ

Хартон, В.В.; Патракеев, М.В.; Tsipis, E.V.; Avdeev, Maxim; Naumovich, E.N.; Anikina, P. V.; Waerenborgh, J.C.

doi:10.1016/j.ssi.2010.06.004

Cited by 30 publications

(41 citation statements)

References 37 publications

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“…For x r0.3, an average value of $ 5.5 was obtained for the total O content per formula unit. These findings agree with observations for similar systems [13,16,27], as well as with an O content of 5.5 derived from TG recordings in 4%H 2 /Ar atmosphere for as-prepared x ¼0.25 (see below).…”

Section: Xrpd Studiessupporting

confidence: 92%

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Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

Samain

Amshoff

Biendicho

et al. 2015

Journal of Solid State Chemistry

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Section: Xrpd Studiessupporting

confidence: 92%

“…As described by Kharton et al [27], this implies that the B cations have locally different possible coordination environments in the structures: (i) o ¼octahedron (no vacancies), (ii) sp ¼square pyramid (O1 vacancy), (iii) tbp ¼trigonal bipyramid (1 O3 vacancy) or (iv) t ¼tetrahedron (1 O1 and 1 O3 vacancy), see Fig. 6.…”

Section: Xrpd Studiesmentioning

confidence: 78%

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

Samain

Amshoff

Biendicho

et al. 2015

Journal of Solid State Chemistry

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“…2. 10 Further types of coordination polyhedra are certainly theoretically possible but we hold them less likely to be present in signicant proportions. For instance, two O3 missing would correspond to a IV-coordination similar to that found for Fe atoms in brownmillerite, although very distorted.…”

Section: Introductionmentioning

confidence: 90%

A structural study of Ruddlesden–Popper phases Sr_3−xY_x(Fe_1.25Ni_0.75)O_7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy

et al. 2018

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IntroductionRuddlesden-Popper (RP) phases are considered as promising candidates for cathode materials in intermediate temperature solid oxide fuel cells (IT-SOFCs) as they can exhibit high mixed oxide-ion and electronic conductivities. 1-4 They have a layered inter-growth structure with alternating layers of perovskite and rock-salt type blocks. A high electronic conductivity may be provided by the perovskite layers and a high oxygen ion mobility by vacancies or interstitials in the rock-salt layers. Phases like Sr 3 Fe 2 O 7Àd have also been studied with respect to their magnetic properties 5 and how they vary with the tuneable parameter of the oxygen content. In a previous study, we investigated RP n ¼ 2 member phases Sr 3Àx Y x Fe 1.25 Ni 0.75 O 7Àd , 0 # x # 0.75. 6 The ideal stoichiometry of an n ¼ 2 RP phase is A 3 B 2 O 7 , where A is an alkaline-earth or rare-earth element, B is a transition metal element, and the structure contains two ABO 3 perovskite layers that alternate with single AO rock-salt layers, For real n ¼ 2 RP phases, the O1 site may be partially or totally vacant and the O3 site may also be partially vacant, while no evidence for O2 vacancies has been found. [8][9][10][11][12][13] The O content per formula unit, 7 À d, may be as low as 5.45.9 For oxygen-decient phases the probable B atom coordination polyhedra are, in varying proportions, octahedra, square pyramids, trigonal bipyramids and tetrahedra, Fig. 2.10 Further types of coordination polyhedra are certainly theoretically possible but we hold them less likely to be present in signicant proportions. For instance, two O3 missing would correspond to a IV-coordination similar to that found for Fe atoms in brownmillerite, although very distorted. The results from XANES suggest, however, that the Fe atoms are predominantly V-coordinated for all x-values.In this study, the structures for een different compositions of Sr 3Àx Y View Article OnlineView Journal | View Issue the study is partly to provide a part of the basis for a better understanding of how RP n ¼ 2 phases can be tailored for IT-SOFC applications and partly to characterize the disorder in the structures from a fundamental point of view. Structural information gained from the NPD data has been supplemented by information from Ni and Fe K-edge EXAFS and XANES spectra. Experimental section Sample preparationThe phases Sr 3Àx Y Time-of-ight (TOF) NPD patterns were collected at room temperature for some of the samples with the POLARIS instrument at ISIS, Rutherford Appleton Laboratory, England, and for the rest with the POWGEN instrument at the Oak Ridge National Laboratory, Tennessee, USA. The structural parameters were rened using the Rietveld method and the Topas soware.14 The space group I4/mmm was used in all renements.Cation compositions were determined by energy dispersive spectroscopy (EDS) micro-analysis with a JEOL 7000F SEM equipped with an Oxford Inca EDS system.Iron and nickel K-edge EXAFS and XANES spectra were measured at the I811 beamline at the MAXlab fac...

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“…This result is consistent with the result of a previous study examining the effect of heat on · under oxidizing conditions. 19) With repeated sintering, the temperature dependence of · appeared to change. After sintering the ceramic sample twice, the slope of the · versus temperature curve changed from positive to negative at ³400°C.…”

Section: +mentioning

confidence: 99%

“…Thermal-electric conversion efficiency is represented by a dimensionless figure of merit, ZT = S 2 ·T/¬, where S, · and ¬ denote the Seebeck coefficient and electrical and thermal conductivities, respectively. According to classical semiconductor theory, heavily doped semiconductors with a carrier concentration (c) of ³10 19 cm ¹3 are suitable high-ZT materials, 1) whereas metallic materials are not. Thus, the discovery of a large S (³100 µV/K at 300 K) for Na x CoO 2 , a p-type oxide material that exhibits a metallic · with a c of ³10 21 cm…”

Section: Introductionmentioning

confidence: 99%

Structural and Thermoelectric Properties of Rare-Earth-Substituted Sr3Fe2O7

et al. 2013

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The structural and thermoelectric properties of rare-earth (Sm)-substituted RuddlesdenPopper-type Sr 3 Fe 2 O 7 , Sr 3¹x Sm x Fe 2 O 7 (SSFO, x = 0, 0.1, 0.15), were investigated by measuring the temperature dependence of its crystallographic parameters, electrical conductivity, and Seebeck coefficient (S). A sharp increase in electrical conductivity (·) up to 60 S/cm (log · = 1.78 S/cm) at 400500°C occurred as a result of oxygen reduction in the x = 0 sample. S values changed from negative to positive with increasing temperature, presumably due to the increase in the number of oxygen vacancies, resulting in Fe ion hopping conduction. The introduction of Sm increased both S and ·, and the power factor of the oxide prepared with x = 0.1 was approximately fivefold higher than that of the oxide with x = 0.

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Oxygen nonstoichiometry, chemical expansion, mixed conductivity, and anodic behavior of Mo-substituted Sr3Fe2O7-δ

Cited by 30 publications

References 37 publications

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

A structural study of Ruddlesden–Popper phases Sr_3−xY_x(Fe_1.25Ni_0.75)O_7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy

Structural and Thermoelectric Properties of Rare-Earth-Substituted Sr<sub>3</sub>Fe<sub>2</sub>O<sub>7</sub>

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Oxygen nonstoichiometry, chemical expansion, mixed conductivity, and anodic behavior of Mo-substituted Sr3Fe2O7-δ

Cited by 30 publications

References 37 publications

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

Crystal structure and high-temperature properties of the Ruddlesden–Popper phases Sr3−Y (Fe1.25Ni0.75)O7− (0≤x≤0.75)

A structural study of Ruddlesden–Popper phases Sr3−xYx(Fe1.25Ni0.75)O7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy

Structural and Thermoelectric Properties of Rare-Earth-Substituted Sr<sub>3</sub>Fe<sub>2</sub>O<sub>7</sub>

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A structural study of Ruddlesden–Popper phases Sr_3−xY_x(Fe_1.25Ni_0.75)O_7−δ with x ≤ 0.75 by neutron powder diffraction and EXAFS/XANES spectroscopy