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http://hdl.handle.net/10773/23716
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DC Field | Value | Language |
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dc.contributor.author | Antunes, I. | pt |
dc.contributor.author | Amador, U. | pt |
dc.contributor.author | Alves, A. | pt |
dc.contributor.author | Correia, M. R. | pt |
dc.contributor.author | Ritter, C. | pt |
dc.contributor.author | Frade, J. R. | pt |
dc.contributor.author | Pérez-Coll, D. | pt |
dc.contributor.author | Mather, G. C. | pt |
dc.contributor.author | Fagg, D. P. | pt |
dc.date.accessioned | 2018-06-29T16:01:27Z | - |
dc.date.issued | 2017 | - |
dc.identifier.issn | 0020-1669 | pt |
dc.identifier.uri | http://hdl.handle.net/10773/23716 | - |
dc.description.abstract | Members of the perovskite solid solution BaZr1−xPrxO3−δ (0.2 ≤ x ≤ 0.8) with potential high-temperature electrochemical applications were synthesized via mechanical activation and high-temperature annealing at 1250 °C. Structural properties were examined by Rietveld analysis of neutron powder diffraction and Raman spectroscopy at room temperature, indicating rhombohedral symmetry (space group R3̅c) for members x = 0.2 and 0.4 and orthorhombic symmetry (Imma) for x = 0.6 and 0.8. The sequence of phase transitions for the complete solid solution from BaZrO3 to BaPrO3 is Pm3̅ m → R3̅c → Imma → Pnma. The structural data indicate that Pr principally exists as Pr4+ on the B site and that oxygen content increases with higher Pr content. Electricalconductivity measurements in the temperature range of 250−900 °C in dry and humidified (pH2O ≈ 0.03 atm) N2 and O2 atmospheres revealed an increase of total conductivity by over 2 orders of magnitude in dry conditions from x = 0.2 to x = 0.8 (σ ≈ 0.08 S cm−1 at 920 °C in dry O2 for x = 0.8). The conductivity for Pr contents x > 0.2 is attributable to positively charged electronic carriers, whereas for x = 0.2 transport in dry conditions is n-type. The change in conduction mechanism with composition is proposed to arise from the compensation regime for minor amounts of BaO loss changing from predominantly partitioning of Pr on the A site to vacancy formation with increasing Pr content. Conductivity is lower in wet conditions for x > 0.2 indicating that the positive defects are, to a large extent, charge compensated by less mobile protonic species. In contrast, the transport mechanism of the Zr-rich composition (x = 0.2), with much lower electronic conductivity, is essentially independent of moisture content | pt |
dc.language.iso | eng | pt |
dc.publisher | American Chemical Society | pt |
dc.relation | FCT-PTDC/CTM-ENE/6319/2014 | pt |
dc.relation | SFRH/BPD/112282/ 2015 | pt |
dc.rights | restrictedAccess | por |
dc.title | Structure and Electrical-Transport Relations in Ba(Zr,Pr)O3-d Perovskites | pt |
dc.type | article | pt |
dc.peerreviewed | yes | pt |
ua.distribution | international | pt |
degois.publication.firstPage | 9120 | pt |
degois.publication.issue | 15 | pt |
degois.publication.lastPage | 9131 | pt |
degois.publication.title | Inorganic Chemistry | pt |
degois.publication.volume | 56 | pt |
dc.date.embargo | 10000-01-01 | - |
dc.identifier.doi | 10.1021/acs.inorgchem.7b01128 | pt |
Appears in Collections: | TEMA - Artigos CICECO - Artigos DFis - Artigos DEM - Artigos DEMaC - Artigos |
Files in This Item:
File | Description | Size | Format | |
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Structure and Electrical-Transport Relations in Ba(Zr,Pr)O3-δ Perovskites.pdf | 3.43 MB | Adobe PDF |
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