Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites

Jihong Cheng; Alexandra Navrotsky

doi:10.1016/S0022-4596(03)00337-2

Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites

Jihong Cheng, Alexandra Navrotsky

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49 Scopus citations

Abstract

LaGaO₃ perovskites doped with Sr or Ba at the La site and Mg at the Ga site were prepared by solid-state reaction or sol-gel method and characterized. Enthalpies of formation from constituent oxides at 298K were determined by high-temperature oxide melt solution calorimetry. Energetic trends are discussed in terms of defect chemistry. As oxygen deficiency increases, formation enthalpies define three trends, LaGa_1-yMg _yO_3-δ (LGM), La_1-xSr_xGa _1-yMg_yO_3-δ (LSGM), and La _1-xBa_xGa_1-yMg_yO_3-δ (LBGM). They become less exothermic with increasing doping, suggesting a dominant destabilization effect from oxygen vacancies. The endothermic enthalpy of vacancy formation is 275±37, 166±18 and 138±12kJ/mol of V_O^.. for LGM, LBGM and LSGM, respectively. Tolerance factor and ion size mismatch also affect enthalpies. In terms of energetics, Sr is the best dopant for the La site and Mg for the Ga site, supporting earlier studies, including oxygen ion conductivity and computer modeling.

Original language	English (US)
Pages (from-to)	126-133
Number of pages	8
Journal	Journal of Solid State Chemistry
Volume	177
Issue number	1
DOIs	https://doi.org/10.1016/S0022-4596(03)00337-2
State	Published - Jan 2004
Externally published	Yes

Keywords

Doped lanthanum gallate
Enthalpy of formation
Oxygen vacancies
Perovskites
Solid electrolyte
Solid oxide fuel cells
Thermodynamics
Tolerance factor

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Condensed Matter Physics
Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

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10.1016/S0022-4596(03)00337-2

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title = "Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites",

abstract = "LaGaO3 perovskites doped with Sr or Ba at the La site and Mg at the Ga site were prepared by solid-state reaction or sol-gel method and characterized. Enthalpies of formation from constituent oxides at 298K were determined by high-temperature oxide melt solution calorimetry. Energetic trends are discussed in terms of defect chemistry. As oxygen deficiency increases, formation enthalpies define three trends, LaGa1-yMg yO3-δ (LGM), La1-xSrxGa 1-yMgyO3-δ (LSGM), and La 1-xBaxGa1-yMgyO3-δ (LBGM). They become less exothermic with increasing doping, suggesting a dominant destabilization effect from oxygen vacancies. The endothermic enthalpy of vacancy formation is 275±37, 166±18 and 138±12kJ/mol of VO.. for LGM, LBGM and LSGM, respectively. Tolerance factor and ion size mismatch also affect enthalpies. In terms of energetics, Sr is the best dopant for the La site and Mg for the Ga site, supporting earlier studies, including oxygen ion conductivity and computer modeling.",

keywords = "Doped lanthanum gallate, Enthalpy of formation, Oxygen vacancies, Perovskites, Solid electrolyte, Solid oxide fuel cells, Thermodynamics, Tolerance factor",

author = "Jihong Cheng and Alexandra Navrotsky",

note = "Funding Information: The authors thank S. Roeske for the help with the electron microprobe analysis. This project was supported by the U.S. Department of Energy (DOE) (Grant DEFG03-97ER45654).",

year = "2004",

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doi = "10.1016/S0022-4596(03)00337-2",

language = "English (US)",

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pages = "126--133",

journal = "Journal of Solid State Chemistry",

issn = "0022-4596",

publisher = "Academic Press Inc.",

number = "1",

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T1 - Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites

AU - Cheng, Jihong

AU - Navrotsky, Alexandra

N1 - Funding Information: The authors thank S. Roeske for the help with the electron microprobe analysis. This project was supported by the U.S. Department of Energy (DOE) (Grant DEFG03-97ER45654).

PY - 2004/1

Y1 - 2004/1

N2 - LaGaO3 perovskites doped with Sr or Ba at the La site and Mg at the Ga site were prepared by solid-state reaction or sol-gel method and characterized. Enthalpies of formation from constituent oxides at 298K were determined by high-temperature oxide melt solution calorimetry. Energetic trends are discussed in terms of defect chemistry. As oxygen deficiency increases, formation enthalpies define three trends, LaGa1-yMg yO3-δ (LGM), La1-xSrxGa 1-yMgyO3-δ (LSGM), and La 1-xBaxGa1-yMgyO3-δ (LBGM). They become less exothermic with increasing doping, suggesting a dominant destabilization effect from oxygen vacancies. The endothermic enthalpy of vacancy formation is 275±37, 166±18 and 138±12kJ/mol of VO.. for LGM, LBGM and LSGM, respectively. Tolerance factor and ion size mismatch also affect enthalpies. In terms of energetics, Sr is the best dopant for the La site and Mg for the Ga site, supporting earlier studies, including oxygen ion conductivity and computer modeling.

AB - LaGaO3 perovskites doped with Sr or Ba at the La site and Mg at the Ga site were prepared by solid-state reaction or sol-gel method and characterized. Enthalpies of formation from constituent oxides at 298K were determined by high-temperature oxide melt solution calorimetry. Energetic trends are discussed in terms of defect chemistry. As oxygen deficiency increases, formation enthalpies define three trends, LaGa1-yMg yO3-δ (LGM), La1-xSrxGa 1-yMgyO3-δ (LSGM), and La 1-xBaxGa1-yMgyO3-δ (LBGM). They become less exothermic with increasing doping, suggesting a dominant destabilization effect from oxygen vacancies. The endothermic enthalpy of vacancy formation is 275±37, 166±18 and 138±12kJ/mol of VO.. for LGM, LBGM and LSGM, respectively. Tolerance factor and ion size mismatch also affect enthalpies. In terms of energetics, Sr is the best dopant for the La site and Mg for the Ga site, supporting earlier studies, including oxygen ion conductivity and computer modeling.

KW - Doped lanthanum gallate

KW - Enthalpy of formation

KW - Oxygen vacancies

KW - Perovskites

KW - Solid electrolyte

KW - Solid oxide fuel cells

KW - Thermodynamics

KW - Tolerance factor

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Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites

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