Solution combustion synthesis of CeFeO3 under ambient atmosphere

Petschnig, Lucas L.; Fuhrmann, Gerda; Schildhammer, Daniel; Tribus, Martina; Schottenberger, Herwig; Huppertz, Hubert

doi:10.1016/j.ceramint.2015.11.102

Cited by 33 publications

(24 citation statements)

References 24 publications

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“…As listed in Table S5, a relative density (D) higher than 95% was achieved for these sintered sheets calculated by the ratio of the bulk density (ρ) determined by the Archimedes method to the theoretical true density (ρ 0 ) reported in previous studies (D = 100 × ρ/ρ 0 ). 58,59 This was further confirmed by the SEM technique (Figure S9a−c). The samples were also confirmed by XRD to be of single perovskite-type structure phase (Figure S9d).…”

Section: Methodssupporting

confidence: 62%

“…Noted that, to obtain the intrinsic diffusion properties of the oxides from ECR experiments, the rectangular bodies of ∼30 × 7 × 1.8 mm used for the ECR test are compressed at a high uniaxial pressure (380 MPa) and sintered at 1500 °C for 5 h in CO 2 atmosphere to ensure the high relative density (ideally larger than 95%), because a lower relative density may result in a relatively large variance of ECR results due to the random porosity pattern in the oxide sheet. As listed in Table S5, a relative density ( D ) higher than 95% was achieved for these sintered sheets calculated by the ratio of the bulk density (ρ) determined by the Archimedes method to the theoretical true density (ρ 0 ) reported in previous studies ( D = 100 × ρ/ρ 0 ). , This was further confirmed by the SEM technique (Figure S9a–c). The samples were also confirmed by XRD to be of single perovskite-type structure phase (Figure S9d).…”

Section: Experimental Detailsmentioning

confidence: 99%

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FeO₆ Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO₂ Splitting

et al. 2020

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Modulating lattice oxygen in metal oxides that conducts partial oxidation of methane in balancing C–H activation and syngas selectivity remains challenging. This paper describes the discovery of distorting FeO6 octahedra in La1–x Ce x FeO3 (x = 0, 0.25 0.5, 0.75, 1) orthorhombic perovskites for the promotion of lattice oxygen activation. By combined electrical conductivity relaxation measurements and density functional theory calculations studies, this paper describes the enhancement of FeO6 octahedral distortion in La1–x Ce x FeO3 promoting their bulk oxygen mobility and surface oxygen exchange capability. Consequently, La0.5Ce0.5FeO3 with the highest FeO6 distortion achieves exceptional syngas productivity of ∼3 and 8 times higher than LaFeO3 and CeFeO3, respectively, in CH4 partial oxidation step with simultaneous high CO2 conversion (92%) in the CO2-splitting step at 850 °C. The results exemplify the feasibility to tailor the active lattice oxygen of perovskite by modulating the distortion of BO6 in ABO3, which ultimately influences their reaction performance in chemical looping processes.

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Section: Methodssupporting

confidence: 62%

Section: Experimental Detailsmentioning

confidence: 99%

FeO₆ Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO₂ Splitting

et al. 2020

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“…RE 6 MoO 12 (RE = Tm–Lu) can usually be prepared by classical solid-state reactions from stoichiometric mixtures of the corresponding oxides RE 2 O 3 and MoO 3 . In our studies, we have employed an alternative route and used the solution combustion (SC) methodology . To the best of our knowledge, this is the first time that this method has been used for the syntheses of rare earth molybdenum oxides.…”

Section: Resultsmentioning

confidence: 99%

Synthetic Access to Cubic Rare Earth Molybdenum Oxides RE₆MoO_12−δ(RE = Tm–Lu) Representing a New Class of Ion Conductors

et al. 2016

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Materials crystallizing in highly symmetric structures are of particular interest as they display superior physical properties in many relevant technological areas such as solid oxide fuels cells (SOFCs), catalysis, or photoluminescent materials. While the rare earth molybdenum oxides RE 6 MoO 12 with the large rare earth cations RE = La to Dy crystallize in a cubic defect fluorite structure type (Fm3̅ m, no. 225), the compounds with the smaller cations RE = Tm− Lu could hitherto only be synthesized in the rhombohedral defect fluorite structure type (R3̅ , no. 148). In the following, new low temperature access to the rare earth molybdenum oxides RE 6 MoO 12−δ (RE = Tm−Lu) crystallizing in the highly symmetric cubic bixbyite structure type (Ia3̅ , no. 206) will be discussed. The three-step method comprises preparation of the rhombohedral phases by solution combustion (SC) reactions, their reduction including simultaneous structural transitions from the rhombohedral to the cubic phases, and subsequent reoxidations while preserving their cubic structures. Detailed studies on this process were performed on the compound Yb 6 MoO 12−δ using TG-DTA, XPS, EDX, and X-ray powder diffraction (XRPD) measurements. In contrast to the rhombohedral phase Yb 6 MoO 12 , which does not show any ionic conductivity, the cubic bixbyite structured compound can be classified as a promising ionic conductor. Electrochemical impedance spectroscopy (EIS) revealed that bulk and grain boundary activation energy determined to be 144.6 kJ mol −1 and 150.4 kJ mol −1 , respectively, range in the same regime as the conventional ionic conductor 8-YSZ. Furthermore, the new cubic phase Yb 6 MoO 12−δ displays improved coloristic properties (UV−Vis spectroscopy) with a yellow hue value (CIE-Lab) being enhanced from b* = 26.0 of the rhombohedral to b* = 46.1 for the cubic phase, which is relevant for the field of inorganic pigments.

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“…As the mole fraction of CeO2 increases, a broadening and an increase in the intensity of the peaks corresponding to cerium oxide are observed, while the relative intensity of the peaks corresponding to o-YbFeO3 does not change. It is known that cerium is capable of forming perovskite-like compounds of the o-CeFeO3 type [22]; however, due to the relatively large ionic radius of Ce 3+ and its low stability in the air, such compounds are oxidized at elevated temperatures with decomposition to more stable CeO2 and iron oxides. For this reason, the cerium orthoferrite phase was not detected in the composition of the samples, and the presence of cerium was observed exclusively in the form of cerium (IV) dioxide.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, structure, and visible-light-driven activity of o-YbFeO₃/h-YbFeO₃/CeO₂ photocatalysts

et al. 2021

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Photo-Fenton-like oxidation of organic substances is one of the key advanced oxidation processes based on the reversible Fe2+↔Fe3+ transition and the generation of a strong oxidant ·OH in the presence of H2O2 and is currently considered as a promising method for the purification of polluted aqueous media. However, the absence of effective and stable photocatalysts of this process, operating under the action of visible light, necessitates the exploratory studies, mainly among iron oxides and ferrites of various compositions and structures. In this work, using the method of solution combustion followed by heat treatment in air the heterojunction nanocomposites based on ytterbium orthoferrite and cerium dioxide of the composition o-YbFeO3/h-YbFeO3/CeO2 (0–20 mol.%) with high absorption in the visible region and advanced photo-Fenton-like activity were obtained. The nanocomposites were studied by EDS, SEM, XRD, BET, and DRS methods. The photo-Fenton-like activity of the nanocomposites was investigated during the degradation of methyl violet under the action of visible (λmax = 410 nm) radiation. As a result, the formation of I-type heterojunction based on stable rhombic (55.4–79.0 nm) and metastable hexagonal (19.5–24.0 nm) modifications of ytterbium orthoferrite (o-YbFeO3 and h-YbFeO3, respectively) and cubic cerium dioxide CeO2 (13.2–19.2 nm) nanocrystals was established. It was shown that the obtained nanocomposites had foamy morphology and were characterized by a specific surface in the range of 9.1–25.0 m2/g, depending on the CeO2 content. It was found that nanocrystalline components were chemically and phase-pure, uniformly spatially distributed over the nanocomposite, and had multiple contacts with each other. Based on this fact and the established electronic structure of the nanocomposite components, the formation of I-type heterojunction with the participation of o-YbFeO3 (Eg = 2.15 eV), h-YbFeO3 (Eg = 2.08 eV), and CeO2 (Eg = 2.38 eV) was shown, the presence of which increased photocatalytic activity of the resulting nanocomposite. The optimal content of CeO2 in the nanocomposite was 5%, and the o-YbFeO3/h-YbFeO3/CeO2–5% sample was characterized by the highest rate constant of photo-Fenton-like degradation of methyl violet under the action of visible light equal to k = 0.138 min–1, which was 2.5 to 5 times higher than for nanocomposites based on ytterbium orthoferrite. The obtained results obtained indicate that the developed nanocomposites can be considered as a promising basis for the advanced oxidation processes for the purification of aqueous media from organic pollutants.

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Solution combustion synthesis of CeFeO3 under ambient atmosphere

Cited by 33 publications

References 24 publications

FeO₆ Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO₂ Splitting

FeO₆ Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO₂ Splitting

Synthetic Access to Cubic Rare Earth Molybdenum Oxides RE₆MoO_12−δ(RE = Tm–Lu) Representing a New Class of Ion Conductors

Synthesis, structure, and visible-light-driven activity of o-YbFeO₃/h-YbFeO₃/CeO₂ photocatalysts

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Solution combustion synthesis of CeFeO3 under ambient atmosphere

Cited by 33 publications

References 24 publications

FeO6 Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO2 Splitting

FeO6 Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO2 Splitting

Synthetic Access to Cubic Rare Earth Molybdenum Oxides RE6MoO12−δ(RE = Tm–Lu) Representing a New Class of Ion Conductors

Synthesis, structure, and visible-light-driven activity of o-YbFeO3/h-YbFeO3/CeO2 photocatalysts

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FeO₆ Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO₂ Splitting

FeO₆ Octahedral Distortion Activates Lattice Oxygen in Perovskite Ferrite for Methane Partial Oxidation Coupled with CO₂ Splitting

Synthetic Access to Cubic Rare Earth Molybdenum Oxides RE₆MoO_12−δ(RE = Tm–Lu) Representing a New Class of Ion Conductors

Synthesis, structure, and visible-light-driven activity of o-YbFeO₃/h-YbFeO₃/CeO₂ photocatalysts