Oxygen sorption/desorption behavior and crystal structural change for SrFeO3−

Ikeda, Hiroshi; Nikata, Soichiro; Hirakawa, Erika; Tsuchida, Akinori; Miura, Norio

doi:10.1016/j.ces.2016.03.034

Cited by 45 publications

(47 citation statements)

References 22 publications

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“…Recently, SrFeO 3 based oxygen sorbents have received many research interests, owing to its large oxygen capacity and low operating temperature [40][41][42]. The versatile structure of SrFeO 3 offers many opportunities to introduce dopants at A and/or B site to further tuning the redox property [43][44][45]. By co-doping of Ca and Co at A and B sites respectively, oxygen partial pressure swing can be operated between 0.05 and 0.2 atm to achieve 1 wt% oxygen capacity at 400 • C-500 • C based on our recent study [46].…”

Section: Introductionmentioning

confidence: 99%

Sr_1-xCa_xFe_1-yCo_yO_3-δ as facile and tunable oxygen sorbents for chemical looping air separation

et al. 2020

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Chemical looping air separation (CLAS) is a promising technology for oxygen generation with high efficiency. The key challenge for CLAS is to design robust oxygen sorbents with suitable redox properties and fast redox kinetics. In this work, perovskite-structured Sr 1-x Ca x Fe 1-y Co y O 3 oxygen sorbents were investigated and demonstrated for oxygen production with tunable redox properties, high redox rate, and excellent thermal/steam stability. Cobalt doping at B site was found to be highly effective, 33% improvement in oxygen productivity was observed at 500 • C. Moreover, it stabilizes the perovskite structure and prevents phase segregation under pressure swing conditions in the presence of steam. Scalable synthesis of Sr 0.8 Ca 0.2 Fe 0.4 Co 0.6 O 3 oxygen sorbents was carried out through solid state reaction, co-precipitation, and sol-gel methods. Both co-precipitation and sol-gel methods are capable of producing Sr 0.8 Ca 0.2 Fe 0.4 Co 0.6 O 3 sorbents with satisfactory phase purity, high oxygen capacity, and fast redox kinetics. Large scale evaluation of Sr 0.8 Ca 0.2 Fe 0.4 Co 0.6 O 3 , using an automated CLAS testbed with over 300 g sorbent loading, further demonstrated the effectiveness of the oxygen sorbent to produce 95% pure O 2 with a satisfactory productivity of 0.04 g O2 g sorbent −1 h −1 at 600 • C.

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Section: Introductionmentioning

confidence: 99%

Sr_1-xCa_xFe_1-yCo_yO_3-δ as facile and tunable oxygen sorbents for chemical looping air separation

et al. 2020

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“…For example, brownmillerite SrCoO 2.5 (SCO) can undergo polymorphic phase transition under electric field control and has resistive switching behavior. 5,[7][8][9][10] Brownmillerite SrFeO x (SFO) with similar structure of SCO has been extensively studied due to its promising application in the fields of electrodes of fuel cell, magnetic storage, redox reaction catalyst, [11][12][13][14][15] etc. In addition, partial substitutions of the B specie of ABO 2.5 produce complex brownmillerite oxides such as Ca 2 FeAlO 5 , Ca 2 FeCoO 5 , etc.…”

Section: Introductionmentioning

confidence: 99%

Atomic occupancy mechanism in brownmillerite Ca₂FeAlO₅ from a thermodynamic perspective

Tao

Zhang

et al. 2019

J Am Ceram Soc

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Brownmillerite‐type oxides are a large family of structural and functional materials that are of great concern. In this study, the occupancy mechanism of Fe and Al ions in brownmillerite Ca2FeAlO5 is revealed and the specific configuration of Ca2FeAlO5 is proposed for the first time. Through the energy analysis of a series of conjectured models based on well‐defined ab initio calculations, we find that the distribution of Al and Fe in Ca2FeAlO5 follows the “homogeneous layer principle”, namely, Al and Fe tend to form homogeneous octahedral layers or tetrahedral chains rather than mixed layers or chains of two elements along the b axis. The theoretical Ca2FeAlO5 structure with specific atomic occupancy is proposed based on energy analysis and previous experiments, which is of fundamental significance for further study of its physical and chemical properties. Moreover, the influence of entropy increment on the stability of Ca2FeAlO5 crystal is clarified, which paves the way to investigate the structures and properties of Ca2FeAlO5 and other brownmillerite members.

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“…The main requirements of electrode materials are (i) to be able to adsorb oxygen from the air and catalytically reduce it (oxygen reduction reaction) or to evolve oxygen and catalytically oxidize the fuel (oxygen evolution reaction), (ii) to possess high mixed ionic and electronic conductivity, (iii) to be highly compatible with the electrolyte in terms of thermal expansion coefficient (TEC), to avoid detrimental effects on the performances and failures in long-term operations.SrFeO 3-δ is a perovskite-type mixed oxide where iron has the expected oxidation state of +4, whereas in most ABO 3 perovskites, like pure and doped LaFeO 3 , the common oxidation state at B-site is +3 [38]. This compound is able to accommodate a large range of oxygen deficiencies, so that some Fe 3+ , with a larger ionic radius, is formed to restore the electroneutrality [40,41]. The oxygen Catalysts 2020, 10, 134 3 of 19 non-stoichiometry is an important factor to achieve high oxygen adsorption, oxygen mobility, and high ionic conductivity [41,42].…”

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confidence: 99%

“…This compound is able to accommodate a large range of oxygen deficiencies, so that some Fe 3+ , with a larger ionic radius, is formed to restore the electroneutrality [40,41]. The oxygen Catalysts 2020, 10, 134 3 of 19 non-stoichiometry is an important factor to achieve high oxygen adsorption, oxygen mobility, and high ionic conductivity [41,42]. Doped SrFeO 3 has been also studied as anodes and as electrodes in electrolyzers due to their high stability in both oxidative and reductive environments [43].It has been already reported that Cerium doping at the A-site of the Strontium Ferrates stabilizes the perovskite cubic structure, with a solubility of about 15 mol% [40,[44][45][46].…”

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confidence: 99%

Sucrose-Assisted Solution Combustion Synthesis of Doped Strontium Ferrate Perovskite-Type Electrocatalysts: Primary Role of the Secondary Fuel

et al. 2020

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The methodologies and experimental conditions used for the synthesis of cathode materials for electrochemical devices strongly influence their electrocatalytic performance. In particular, solution combustion synthesis is a convenient and versatile methodology allowing a fine-tuning of the properties of the material. In this work, we used for the first time a sucrose assisted-solution combustion synthesis for the preparation of Cerium and Cobalt-doped SrFeO3–δ electrocatalysts and we investigated the effect of polyethylene glycol (PEG) addition as a secondary fuel on their structural, microstructural, redox and electrochemical properties. The perovskite-type powders were characterized by X-ray diffraction coupled with Rietveld refinement, scanning, and high-resolution transmission electron microscopies, thermogravimetric analysis, nitrogen adsorption measurements, and temperature-programmed reduction. Electrical conductivity and overpotential measurements were performed after the deposition of the powders onto a Gd-doped ceria electrolyte pellet. Stable high-valence B-site cations were detected in the powders prepared from sucrose-PEG fuel mixtures, although a substantial improvement of the conductivity and a decrease of the overpotential values were obtained only with high molecular weight PEG. The superior electrochemical performance obtained using PEG with high molecular weight has been ascribed to a faster interaction of the powder with the oxygen gas phase favored by the nanometer-sized crystalline domains.

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Oxygen sorption/desorption behavior and crystal structural change for SrFeO3−

Cited by 45 publications

References 22 publications

Sr_1-xCa_xFe_1-yCo_yO_3-δ as facile and tunable oxygen sorbents for chemical looping air separation

Sr_1-xCa_xFe_1-yCo_yO_3-δ as facile and tunable oxygen sorbents for chemical looping air separation

Atomic occupancy mechanism in brownmillerite Ca₂FeAlO₅ from a thermodynamic perspective

Sucrose-Assisted Solution Combustion Synthesis of Doped Strontium Ferrate Perovskite-Type Electrocatalysts: Primary Role of the Secondary Fuel

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Oxygen sorption/desorption behavior and crystal structural change for SrFeO3−

Cited by 45 publications

References 22 publications

Sr1-xCaxFe1-yCoyO3-δ as facile and tunable oxygen sorbents for chemical looping air separation

Sr1-xCaxFe1-yCoyO3-δ as facile and tunable oxygen sorbents for chemical looping air separation

Atomic occupancy mechanism in brownmillerite Ca2FeAlO5 from a thermodynamic perspective

Sucrose-Assisted Solution Combustion Synthesis of Doped Strontium Ferrate Perovskite-Type Electrocatalysts: Primary Role of the Secondary Fuel

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Sr_1-xCa_xFe_1-yCo_yO_3-δ as facile and tunable oxygen sorbents for chemical looping air separation

Sr_1-xCa_xFe_1-yCo_yO_3-δ as facile and tunable oxygen sorbents for chemical looping air separation

Atomic occupancy mechanism in brownmillerite Ca₂FeAlO₅ from a thermodynamic perspective