Synthesis and characterization of polycrystalline brownmillerite cobalt doped Ca2Fe2O5

Dhankhar, Suchita; Bhalerao, G. M.; Baskar, K.; Singh, Shubra

doi:10.1063/1.4948198

Cited by 9 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, synthesis efforts under the same conditions as the other materials led to a different structure, i.e., regular brownmillerite, comprising a single octahedral layer alternating with a tetrahedral layer. The product had the formula Ca 3 Fe 3 O 8−δ , where δ = 0.5, (i.e., Ca 2 Fe 2 O 5 ) and crystallized in the Pnma space group, as previously reported. , (Figure S2 and Table S1).…”

Section: Resultssupporting

confidence: 67%

See 1 more Smart Citation

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca₃Fe_3–xMn_xO₈ (x = 1–2) for the Hydrogen Evolution Reaction

Wickramaratne,

Karki,

Ramezanipour

2023

Inorg. Chem.

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 67%

“…The product had the formula Ca 3 Fe 3 O 8−δ , where δ = 0.5, (i.e., Ca 2 Fe 2 O 5 ) and crystallized in the Pnma space group, as previously reported. 40,41 (Figure S2 and Table S1).…”

Section: Resultsmentioning

confidence: 99%

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca₃Fe_3–xMn_xO₈ (x = 1–2) for the Hydrogen Evolution Reaction

Wickramaratne,

Karki,

Ramezanipour

2023

Inorg. Chem.

View full text Add to dashboard Cite

“…This phenomenon may be attributed to the presence of the Ca 2 Fe 2 O 5 phase, as reported in the XRD section. Ca 2 Fe 2 O 5 exhibits hole-type electronic conduction due to oxygen interstitials in the structure at lower temperatures, while a phase transition takes place at ∼600 °C, resulting in a lower level of oxygen and thus lower electrical conductivity at higher temperatures . Moreover, the conductivity of LC x CF materials increased with increasing Ca content and reached a maximum when x = 0.4, accounting for the increasing formation of oxygen vacancies created by charge compensation due to a higher amount of divalent alkaline-earth Ca ion substitution for La .…”

Section: Resultsmentioning

confidence: 99%

“…Ca 2 Fe 2 O 5 exhibits hole-type electronic conduction due to oxygen interstitials in the structure at lower temperatures, while a phase transition takes place at ∼600 °C, resulting in a lower level of oxygen and thus lower electrical conductivity at higher temperatures. 46 Moreover, the conductivity of LCxCF materials increased with increasing Ca content and reached a maximum when x = 0.4, accounting for the increasing formation of oxygen vacancies created by charge compensation due to a higher amount of divalent alkaline-earth Ca ion substitution for La. 18 However, the conductivity of LCCF55 and LCCF46 gradually decreased, which may be attributed to the increased amount of Ca 2 Fe 2 O 5 , which exhibits very low conductivity compared with the LCxCF perovskite structure.…”

Section: Co 2 Adsorptionmentioning

confidence: 99%

Unlocking the Potential of A-Site Ca-Doped LaCo_0.2Fe_0.8O_3−δ: A Redox-Stable Cathode Material Enabling High Current Density in Direct CO₂ Electrolysis

Li,

Wang,

Wang

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Massive carbon dioxide (CO2) emission from recent human industrialization has affected the global ecosystem and raised great concern for environmental sustainability. The solid oxide electrolysis cell (SOEC) is a promising energy conversion device capable of efficiently converting CO2 into valuable chemicals using renewable energy sources. However, Sr-containing cathode materials face the challenge of Sr carbonation during CO2 electrolysis, which greatly affects the energy conversion efficiency and long-term stability. Thus, A-site Ca-doped La1–x Ca x Co0.2Fe0.8O3−δ (0.2 ≤ x ≤ 0.6) oxides are developed for direct CO2 conversion to carbon monoxide (CO) in an intermediate-temperature SOEC (IT-SOEC). With a polarization resistance as low as 0.18 Ω cm2 in pure CO2 atmosphere, a remarkable current density of 2.24 A cm–2 was achieved at 1.5 V with La0.6Ca0.4Co0.2Fe0.8O3−δ (LCCF64) as the cathode in La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) electrolyte (300 μm) supported electrolysis cells using La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) as the air electrode at 800 °C. Furthermore, symmetrical cells with LCCF64 as the electrodes also show promising electrolysis performance of 1.78 A cm–2 at 1.5 V at 800 °C. In addition, stable cell performance has been achieved on direct CO2 electrolysis at an applied constant current of 0.5 A cm–2 at 800 °C. The easily removable carbonate intermediate produced during direct CO2 electrolysis makes LCCF64 a promising regenerable cathode. The outstanding electrocatalytic performance of the LCCF64 cathode is ascribed to the highly active and stable metal/perovskite interfaces that resulted from the in situ exsolved Co/CoFe nanoparticles and the additional oxygen vacancies originated from the Ca2Fe2O5 phase synergistically providing active sites for CO2 adsorption and electrolysis. This study offers a novel approach to design catalysts with high performance for direct CO2 electrolysis.

show abstract

“…For many years, the subject was ignored because the rates of oxide-ion transport were so low. It was the high-temperature, oxygen-deficient perovskite (PV) phase ABO 3−δ that received attention, mainly due to its potential application in solid oxide fuel cell and oxygen permeable membrane technologies. − Currently, the reversible phase transition between BM and PV phases, generated at constant temperature by adding oxygen to the BM phase or removing oxygen from the PV phase, is attracting attention for nonvolatile-memory and artificial-synaptic devices. − …”

Section: Introductionmentioning

confidence: 99%

Oxygen Diffusion in Brownmillerite Sr₂Fe₂O₅ is Two-Dimensional: Results from a Molecular Dynamics Study

Ambaum,

Allan,

Dittmann

et al. 2024

Chem. Mater.

View full text Add to dashboard Cite

Electrically insulating A2B2O5 brownmillerite materials can be transformed through a reversible, topotactic phase transition to conducting ABO3−δ perovskite phases. Such systems are of emerging interest for resistive random-access devices. The key process for the phase transition is oxygen diffusion, but to date, experimental or computational studies yielding oxygen diffusion coefficients in brownmillerite materials are rare. In this study, we use molecular dynamics simulations to directly investigate oxygen tracer diffusion in the brownmillerite Sr2Fe2O5 phase and the SrFeO2.5 perovskite phase. Our results for brownmillerite Sr2Fe2O5 go beyond computed diffusion coefficients: They indicate that oxygen vacancies execute two-dimensional diffusion between the equatorial sites of the FeO6 octahedra, and surprisingly, that oxygen interstitials are not confined to the oxygen-vacancy channels (as widely assumed in the literature) but migrate two-dimensionally by interstitial and interstitialcy mechanisms in the FeO4 layers. Comparisons with experimental data are possible for the perovskite phase, and good agreement is found between simulation and experiment for the oxygen-vacancy diffusivity in terms of both absolute magnitude and activation enthalpy.

show abstract

Synthesis and characterization of polycrystalline brownmillerite cobalt doped Ca2Fe2O5

Cited by 9 publications

References 5 publications

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca₃Fe_3–xMn_xO₈ (x = 1–2) for the Hydrogen Evolution Reaction

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca₃Fe_3–xMn_xO₈ (x = 1–2) for the Hydrogen Evolution Reaction

Unlocking the Potential of A-Site Ca-Doped LaCo_0.2Fe_0.8O_3−δ: A Redox-Stable Cathode Material Enabling High Current Density in Direct CO₂ Electrolysis

Oxygen Diffusion in Brownmillerite Sr₂Fe₂O₅ is Two-Dimensional: Results from a Molecular Dynamics Study

Contact Info

Product

Resources

About

Synthesis and characterization of polycrystalline brownmillerite cobalt doped Ca2Fe2O5

Cited by 9 publications

References 5 publications

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca3Fe3–xMnxO8 (x = 1–2) for the Hydrogen Evolution Reaction

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca3Fe3–xMnxO8 (x = 1–2) for the Hydrogen Evolution Reaction

Unlocking the Potential of A-Site Ca-Doped LaCo0.2Fe0.8O3−δ: A Redox-Stable Cathode Material Enabling High Current Density in Direct CO2 Electrolysis

Oxygen Diffusion in Brownmillerite Sr2Fe2O5 is Two-Dimensional: Results from a Molecular Dynamics Study

Contact Info

Product

Resources

About

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca₃Fe_3–xMn_xO₈ (x = 1–2) for the Hydrogen Evolution Reaction

Electrocatalytic Properties of Oxygen-Deficient Perovskites Ca₃Fe_3–xMn_xO₈ (x = 1–2) for the Hydrogen Evolution Reaction

Unlocking the Potential of A-Site Ca-Doped LaCo_0.2Fe_0.8O_3−δ: A Redox-Stable Cathode Material Enabling High Current Density in Direct CO₂ Electrolysis

Oxygen Diffusion in Brownmillerite Sr₂Fe₂O₅ is Two-Dimensional: Results from a Molecular Dynamics Study