Defects, Dopants, and Protons in LaNbO4

Simulation methods have been used to investigate the energetics of defect formation, dopant solution, water incorporation, and defect clustering in the high-temperature proton conductor LaNbO4. The interatomic potential model successfully reproduces the observed tetragonal scheelite-type structure o...

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Veröffentlicht in:Chemistry of materials 2010-11, Vol.22 (21), p.5912-5917
Hauptverfasser: Mather, Glenn C, Fisher, Craig A.J, Islam, M. Saiful
Format: Artikel
Sprache:eng
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Zusammenfassung:Simulation methods have been used to investigate the energetics of defect formation, dopant solution, water incorporation, and defect clustering in the high-temperature proton conductor LaNbO4. The interatomic potential model successfully reproduces the observed tetragonal scheelite-type structure of LaNbO4. Formation of an oxygen vacancy, required for protonation, is accompanied by significant local relaxation leading to an [Nb2O7]4− group. The most favorable dopant solution energies are found for Ca2+ and Sr2+ on the La site. Dopant-vacancy association is predicted to occur for a wide range of divalent dopants on the La site and tetravalent dopants on the Nb site. Dopant-proton association is also predicted to occur for the range of dopants studied. The lowest M/ − OH• binding energy is found for Ca, which is commonly used in compositions displaying the highest proton conductivities so far reported in the LaNbO4 system.
ISSN:0897-4756
1520-5002
DOI:10.1021/cm1018822