Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 133, Issue 44, Pages 17662-17672Publisher
AMER CHEMICAL SOC
DOI: 10.1021/ja2053557
Keywords
-
Categories
Funding
- NSF [DMR0804737, CHE0714183]
- French Foreign Office [530227G]
- EPSRC
- BBSRC
- University of Warwick
- Advantage West Midlands (AWM)
- European Regional Development Fund (ERDF)
- U.S. Department of Energy, Office of Basic Energy Sciences [DE-AC02-98CH10886]
- National High Magnetic Field Laboratory through National Science Foundation [DMR0654118]
- State of Florida
- EPSRC [EP/F017901/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [EP/F017901/1] Funding Source: researchfish
Ask authors/readers for more resources
Doped lanthanum gallate perovskites (LaGaO3) constitute some of the most promising electrolyte materials for solid oxide fuel cells operating in the intermediate temperature regime. Here, an approach combining experimental multinuclear NMR spectroscopy with density functional theory total energy and GIPAW NMR calculations yields a comprehensive understanding of the structural and defect chemistries of,Sr- and Mg-doped LaGaO3 anionic conductors. The DFT energetics demonstrate that Ga-V-O-Ga (V-O = oxygen vacancy) environments are favored (vs Ga-V-O-Mg, Mg-V-O-Mg and Mg-O-Mg-V-O-Ga) across a range y = 0.0625, 0.125, and 0.25 of fractional Mg contents in LaGa1-yMgyO3-y/2. The results are interpreted in terms of doping and mean phase formation energies (relative to binary oxides) and are compared with previous calculations and experimental calorimetry, data Experimental multinuclear NMR data reveal that while Mg sites remain six fold coordinated across the range of phase stoichiometries, albeit with significant structural disorder, a stoichiometry dependent minority of the Ga sites resonate at a shift consistent with Ga-V coordination, demonstrating that O vacancies preferentially locate in the first anion coordination shell of Ga. The strong Mg-V-O binding inferred by previous studies is not observed here. The O-17 NMR spectra reveal distinct resonances that Can be assigned by using the GIPAW NMR. calculations to anions occupying equatorial and axial positions with respect to the Ga-V-V-O axis. The disparate shifts displayed by these sites are due to the nature and extent of the structural distortions caused by the O vacancies. vs.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available