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Wollstadt S, Ikeda Y, Sarkar A, Vasala S, Fasel C, Alff L, Kruk R, Grabowski B, Clemens O. Structural and Magnetic Properties of BaFeO 2.667 Synthesized by Oxidizing BaFeO 2.5 Obtained via Nebulized Spray Pyrolysis. Inorg Chem 2021; 60:10923-10933. [PMID: 34240868 DOI: 10.1021/acs.inorgchem.1c00434] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A vacancy-ordered perovskite-type compound Ba3Fe3O8 (BaFeO2.667) was prepared by oxidizing BaFeO2.5 (P21/c) with the latter compound obtained by a spray pyrolysis technique. The structure of Ba3Fe3O8 was found to be isotypic to Ba3Fe3O7F (P21/m) and can be written as Ba3Fe3+2Fe4+1O8. Mössbauer spectroscopy and ab initio calculations were used to confirm mixed iron oxidation states, showing allocation of the tetravalent iron species on the tetrahedral site, and octahedral as well as square pyramidal coordination for the trivalent species within a G-type antiferromagnetic ordering. The uptake and release of oxygen were investigated over a broad temperature range from room temperature to 1100 °C under pure oxygen and ambient atmosphere via a combination of DTA/TG and variable temperature diffraction measurements. The compound exhibited a strong lattice enthalpy driven reduction to monoclinic and cubic BaFeO2.5 at elevated temperatures.
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Affiliation(s)
- Stephan Wollstadt
- Institute for Materials Science, Materials Synthesis Group, University of Stuttgart, Heisenbergstraße 3, Stuttgart 70569, Germany.,Institut für Materialwissenschaft, Fachgebiet Materialdesign durch Synthese, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
| | - Yuji Ikeda
- Institute for Materials Science, Department of Materials Design, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Abhishek Sarkar
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, Eggenstein Leopoldshafen 76344, Germany.,Institut für Materialwissenschaft, Gemeinschaftslabor Nanomaterialien, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
| | - Sami Vasala
- Institut für Materialwissenschaft, Fachgebiet Materialdesign durch Synthese, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
| | - Claudia Fasel
- Institut für Materialwissenschaft, Fachgebiet Disperse Feststoffe, Technical University of Darmstadt Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany
| | - Lambert Alff
- Institut für Materialwissenschaft, Advanced Thin Film Technology, Technical University of Darmstadt Alarich-Weiss-Straße 2, 64287 Darmstadt, Germany
| | - Robert Kruk
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, Eggenstein Leopoldshafen 76344, Germany
| | - Blazej Grabowski
- Institute for Materials Science, Department of Materials Design, University of Stuttgart, Pfaffenwaldring 55, Stuttgart 70569, Germany
| | - Oliver Clemens
- Institute for Materials Science, Materials Synthesis Group, University of Stuttgart, Heisenbergstraße 3, Stuttgart 70569, Germany.,Institut für Materialwissenschaft, Fachgebiet Materialdesign durch Synthese, Technical University of Darmstadt, Alarich-Weiss-Straße 2, Darmstadt 64287, Germany
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Iqbal Waidha A, Khatoon Siddiqui H, Ikeda Y, Lepple M, Vasala S, Donzelli M, Fortes AD, Slater P, Grabowski B, Kramm UI, Clemens O. Structural, Magnetic and Catalytic Properties of a New Vacancy Ordered Perovskite Type Barium Cobaltate BaCoO 2.67. Chemistry 2021; 27:9763-9767. [PMID: 33908660 PMCID: PMC8361746 DOI: 10.1002/chem.202101167] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Indexed: 12/01/2022]
Abstract
A new vacancy ordered, anion deficient perovskite modification with composition of BaCoO2.67 (Ba3Co3O8□1) has been prepared via a two‐step heating process. Combined Rietveld analysis of neutron and X‐ray powder diffraction data shows a novel ordering of oxygen vacancies not known before for barium cobaltates. A combination of neutron powder diffraction, magnetic measurements, and density functional theory (DFT) studies confirms G‐type antiferromagnetic ordering. From impedance measurements, the electronic conductivity of the order of 10−4 S cm−1 is determined. Remarkably, the bifunctional catalytic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is found to be comparable to that of Ba0.5Sr0.5Co0.8Fe0.2O3–y, confirming that charge‐ordered anion deficient non‐cubic perovskites can be highly efficient catalysts.
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Affiliation(s)
- Aamir Iqbal Waidha
- Materials Synthesis Group, Institute of Material Science, University of Stuttgart, Hesisenbergstraße 3, 70569, Stuttgart, Germany
| | - Humera Khatoon Siddiqui
- Catalysts and Electrocatalyst, Department of Chemistry, Eduard-Zintl Institute for Inorganic and Physical Chemistry, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Yuji Ikeda
- Department of Materials Design, Institute for Materials Science, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Maren Lepple
- DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, 60486, Frankfurt am Main, Germany
| | - Sami Vasala
- Materials Synthesis Group, Institute of Material Science, University of Stuttgart, Hesisenbergstraße 3, 70569, Stuttgart, Germany
| | - Manuel Donzelli
- Materials Synthesis Group, Institute of Material Science, University of Stuttgart, Hesisenbergstraße 3, 70569, Stuttgart, Germany
| | - A D Fortes
- Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, ISIS Facility, Didcot, Oxfordshire, OX11 0QX, UK
| | - Peter Slater
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Blazej Grabowski
- Department of Materials Design, Institute for Materials Science, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Ulrike I Kramm
- Catalysts and Electrocatalyst, Department of Chemistry, Eduard-Zintl Institute for Inorganic and Physical Chemistry, Technische Universität Darmstadt, 64287, Darmstadt, Germany
| | - Oliver Clemens
- Materials Synthesis Group, Institute of Material Science, University of Stuttgart, Hesisenbergstraße 3, 70569, Stuttgart, Germany
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Wollstadt S, Clemens O. On the Impact of the Degree of Fluorination on the ORR Limiting Processes within Iron Based Catalysts: A Model Study on Symmetrical Films of Barium Ferrate. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E2532. [PMID: 32503126 PMCID: PMC7321444 DOI: 10.3390/ma13112532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 12/21/2022]
Abstract
In this study, symmetrical films of BaFeO2.67, BaFeO2.33F0.33 and BaFeO2F were synthesized and the oxygen uptake and conduction was investigated by high temperature impedance spectroscopy under an oxygen atmosphere. The data were analyzed on the basis of an impedance model designed for highly porous mixed ionic electronic conducting (MIEC) electrodes. Variable temperature X-ray diffraction experiments were utilized to estimate the stability window of the oxyfluoride compounds, which yielded a degradation temperature for BaFeO2.33F0.33 of 590 °C and a decomposition temperature for BaFeO2F of 710 °C. The impedance study revealed a significant change of the catalytic behavior in dependency of the fluorine content. BaFeO2.67 revealed a bulk-diffusion limited process, while BaFeO2.33F0.33 appeared to exhibit a fast bulk diffusion and a utilization region δ larger than the electrode thickness L (8 μm). In contrast, BaFeO2F showed very area specific resistances due to the lack of oxygen vacancies. The activation energy for the uptake and conduction process of oxygen was found to be 0.07/0.29 eV (temperature range-dependent), 0.33 eV and 0.67 eV for BaFeO2.67, BaFeO2.33F0.33 and BaFeO2F, respectively.
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Affiliation(s)
- Stephan Wollstadt
- Fachgebiet Materialdesign Durch Synthese, Institut für Materialwissenschaft, Technical University of Darmstadt, 64287 Darmstadt, Germany;
| | - Oliver Clemens
- Fachgebiet Materialdesign Durch Synthese, Institut für Materialwissenschaft, Technical University of Darmstadt, 64287 Darmstadt, Germany;
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein Leopoldshafen, Germany
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Nair A, Wollstadt S, Witte R, Dasgupta S, Kehne P, Alff L, Komissinskiy P, Clemens O. Synthesis and characterisation of fluorinated epitaxial films of BaFeO2F: tailoring magnetic anisotropyviaa lowering of tetragonal distortion. RSC Adv 2019; 9:37136-37143. [PMID: 35542307 PMCID: PMC9075590 DOI: 10.1039/c9ra08039b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 10/25/2019] [Indexed: 01/11/2023] Open
Abstract
In this article, we report on the synthesis and characterisation of fluorinated epitaxial films of BaFeO2F via low-temperature fluorination of thin films of BaFeO2.5+d grown by pulsed laser deposition. Diffraction measurements show that fluoride incorporation only results in a contraction of the film perpendicular to the film surface, where clamping by the substrate is prohibitive for strong in-plane changes. The fluorinated films were found to be homogenous regarding the fluorine content over the whole film thickness, and can be considered as single crystal equivalents to the bulk phase BaFeO2F. Surprisingly, fluorination resulted in the change of the tetragonal distortion to a nearly cubic symmetry, which results in a lowering of anisotropic orientation of the magnetic moments of the antiferromagnetically ordered compound, confirmed by Mössbauer spectroscopy and magnetic studies. Fluorination of epitaxially grown thin films of BaFeO2.5 to BaFeO2F results in increased magnetic anisotropy.![]()
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Affiliation(s)
- Akash Nair
- Technische Universität Darmstadt
- Institute of Materials Science
- Materials Design by Synthesis Division
- 64287 Darmstadt
- Germany
| | - Stephan Wollstadt
- Technische Universität Darmstadt
- Institute of Materials Science
- Materials Design by Synthesis Division
- 64287 Darmstadt
- Germany
| | - Ralf Witte
- Karlsruhe Institute of Technology
- Institute of Nanotechnology
- 76344 Eggenstein Leopoldshafen
- Germany
| | - Supratik Dasgupta
- Technische Universität Darmstadt
- Institute of Materials Science
- Advanced Thin Film Technology Division
- 64287 Darmstadt
- Germany
| | - Philipp Kehne
- Technische Universität Darmstadt
- Institute of Materials Science
- Advanced Thin Film Technology Division
- 64287 Darmstadt
- Germany
| | - Lambert Alff
- Technische Universität Darmstadt
- Institute of Materials Science
- Advanced Thin Film Technology Division
- 64287 Darmstadt
- Germany
| | - Philipp Komissinskiy
- Technische Universität Darmstadt
- Institute of Materials Science
- Advanced Thin Film Technology Division
- 64287 Darmstadt
- Germany
| | - Oliver Clemens
- Technische Universität Darmstadt
- Institute of Materials Science
- Materials Design by Synthesis Division
- 64287 Darmstadt
- Germany
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Chikamatsu A, Kawahara K, Shiina T, Onozuka T, Katayama T, Hasegawa T. Fabrication of Fluorite-Type Fluoride Ba 0.5Bi 0.5F 2.5 Thin Films by Fluorination of Perovskite BaBiO 3 Precursors with Poly(vinylidene fluoride). ACS OMEGA 2018; 3:13141-13145. [PMID: 31458034 PMCID: PMC6644648 DOI: 10.1021/acsomega.8b02252] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/01/2018] [Indexed: 05/28/2023]
Abstract
Metal fluorides are gathering significant interest for use in many applications, such as optical glasses, chemical sensors, and solid electrolytes using fluoride ion batteries, due to their high transparency over a wide wavelength range (ultraviolet to infrared) and fast fluoride ion conductivity. Here, we present a topotactic route for synthesizing thin films of fluorite-type Ba0.5Bi0.5F2.5 (BBF), a promising fluoride ion conductor, from perovskite-type BaBiO3 (BBO) precursor films by fluorination using poly(vinylidene fluoride). The fluorination reaction fully converted BBO to BBF without stopping at the oxyfluoride stage. The BBF films obtained at relatively low reaction temperatures (150-200 °C) showed Ba/Bi cation ordering in the [001] direction, indicating that the cation framework of perovskite BBO was maintained during the fluorination reaction. Meanwhile, increasing the fluorination temperature led to mixtures of cations, resulting in random distribution of Ba and Bi. This demonstrates that the degree of cation ordering in BBF can be controlled by adjusting the fluorination temperature.
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Katsumata T, Sawada N, Kuraya R, Hamagaki T, Aimi A, Mori D, Inaguma Y, Wang RP. Phase transitions and dielectric properties of perovskite-type oxyfluorides (1-x)KNbO3-xKMgF3. J Fluor Chem 2018. [DOI: 10.1016/j.jfluchem.2018.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Assembly of 6-aminonicotinic acid and inorganic anions into different dimensionalities: Crystal structure, absorption properties and Hirshfeld surface analysis. Polyhedron 2017. [DOI: 10.1016/j.poly.2016.12.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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