First mixed-metal fluoride pyrochlores obtained by topotactic oxidation of ammonium fluorides under F2 gas
| Autor: | Annie Hémon-Ribaud, Elena M. Arroyo-de Dompablo, Kévin Lemoine, Romain Moury, Emilio Morán, Veyis Gunes, Jérôme Lhoste, Etienne Durand, Marc Leblanc, Cyrille Galven, Jean-Marc Greneche, Vincent Maisonneuve |
|---|---|
| Přispěvatelé: | Institut des Molécules et Matériaux du Mans (IMMM), Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Departamento de Quimica Inorganica y Bioinorganica [Madrid], Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), The authors thank the French Research Ministry for a doctoral grant. The authors attached to the IMMM institute gratefully acknowledge the 'X-ray Diffusion and Diffraction' and the 'Electron Microscopy' technical platforms of IMMM (Le Mans University). E.M. thanks the MINECO and Agencia Estatal de Investigación (AEI)/Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the Projects MAT2016-78362-C4-4-R and PID2019-106662RB-C44. |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Anions
Materials science Inorganic chemistry Pyrochlore chemistry.chemical_element engineering.material Tungsten 010402 general chemistry 01 natural sciences Catalysis Metal chemistry.chemical_compound Chemical structure Cations Oxidation General Materials Science Ammonium Bronze 010405 organic chemistry General Chemistry Transition metals [CHIM.MATE]Chemical Sciences/Material chemistry Condensed Matter Physics 0104 chemical sciences chemistry visual_art Electrode visual_art.visual_art_medium engineering Fluoride |
| Zdroj: | Crystal Growth & Design Crystal Growth & Design, American Chemical Society, 2021, 21 (2), pp.935-945. ⟨10.1021/acs.cgd.0c01279⟩ |
| ISSN: | 1528-7483 1528-7505 |
| DOI: | 10.1021/acs.cgd.0c01279⟩ |
| Popis: | International audience; Metal fluorides with 3D open structures, pyrochlore (pyr) or hexagonal tungsten bronze (HTB), are promising materials as positive electrodes for rechargeable batteries or catalysts. Herein, we have developed a two-step synthesis procedure to obtain new anhydrous mixed-metal-cation fluorides crystallizing in the pyrochlore structure. The first step consists of preparing mixed-metal ammonium fluorides (NH4)M2+Fe3+F6 (M = Mn, Fe, Co Ni) using different synthesis strategies. For M = Mn, three allotropic varieties of (NH4)Mn2+Fe3+F6 are obtained; two phases adopt the expected pyrochlore network with either the cubic Fm3̅m or the orthorhombic Pnma space group, and the third phase exhibits a 3D network with narrow pseudotriangular cavities. 57Fe Mössbauer spectrometry indicates that the crystal structures are governed by the Fe3+/Mn2+ cationic order or disorder. The second step is a topotactic oxidation of pyr-(NH4)M2+Fe3+F6 under a molecular F2 flow. To better understand the reaction mechanism, the topotactic oxidation was followed by thermogravimetry, XRD, FTIR, and Mössbauer spectrometry. The successful synthesis of the first anhydrous pyr-M3+0.5Fe0.5F3 provides a new route to prepare anhydrous mixed-metal fluorides pyrochlore with empty cavities of the open framework. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|