Distinct intercalation and conduction behaviors within an isostructural series Ba5R2Al2SnO1
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Date
2024-07-30
Journal Title
Journal ISSN
Volume Title
Publisher
American Chemical Society
Abstract
The series Ba5R2Al2SnO13 (R = In, Y, Er, Ho, Tb) has been synthesized and structurally characterized by X-ray and neutron powder diffraction. All members have oxygen-deficient 10-layer hexagonal (10H) perovskite-type structures at high temperature and gain mass on cooling equivalent to ∼0.5 oxygen atoms per formula unit, observed by both thermogravimetric analysis and the occupancy of a vacant site in the oxygen substructure refined against neutron powder diffraction data. The origin of this mass gain varies with R: for R = In, Y, Er, and Ho, it is due to water uptake via a hydroxylation mechanism to form Ba5R2Al2SnO13.xH2O (x ≤ 0.5), with OH– ions occupying the vacant site and the other proton forming a second OH– in the oxygen substructure; while for R = Tb, it due to the oxidation of Tb3+ to Tb4+, with O2– ions occupying the vacant site. These chemico-structural differences are consistent with the measured conductivity behavior of the samples, whereby Ba5Er2Al2SnO13 is a proton conductor in air at moderate temperatures (∼10–4 S cm–1 at 500 °C) while Ba5Tb2Al2SnO13 is a mixed oxide ionic and electronic conductor. These differences were further confirmed by X-ray absorption spectroscopy and corroborated by quasielastic neutron scattering. © 2024 American Chemical Society.
Description
Keywords
Aluminium, Rhenium, Barium, Neutron diffraction, Temperature range, Oxides, Electric conductors, Spectroscopy, Atmospheric chemistry, Granular materials, Oxygen
Citation
Brown, A. J., Wagstaff, O. J., Evans, I. R., Evans, J. S. O., Mole, R. A., Wykes, J., Avdeev, M., & Ling, C. D. (2024). Distinct intercalation and conduction behaviors within an isostructural series Ba5R2Al2SnO13. Chemistry of Materials, 36(17), 8188-8198. doi:10.1021/acs.chemmater.4c00580