Rare-Earth-Substituted Strontium Titanate: Insight into Local Oxygen-Rich Structures and Redox Kinetics
authors Yaremchenko, AA; Naumovich, EN; Patricio, SG; Merkulov, OV; Patrakeev, MV; Frade, JR
nationality International
journal INORGANIC CHEMISTRY
keywords LA-DOPED SRTIO3; OXIDE FUEL-CELLS; TEMPERATURE STEAM ELECTROLYSIS; ANODE MATERIALS; THERMOELECTRIC PERFORMANCE; ELECTRICAL-PROPERTIES; DEFECT CHEMISTRY; CERIUM DIOXIDE; SINGLE-CRYSTAL; SOFC ANODES
abstract Ln-substituted SrTiO3 is a promising material for energy conversion technologies such as. thermoelectric generators and solid oxide fuel/electrolysis cells. In this study, formation of local structures enabling accommodation of excess oxygen in perovskite matrix of SrTiO3 and related redox behavior were assessed employing static lattice simulations in combination with experimental methods (XRD, SEM/EDS, XPS, TGA, and electrical measurements) using Sr(0.90-x)Ln(0.10)TiO(3 +/-delta) (Ln = Ce, Pr; x = 0-0.10) as model systems. Although strontium-vacancy formation is found to be a preferable mechanism for donor compensation in oxidized Sr(Ln)TiO3, oxygen excess still can be accommodated by extended defects quenched from high temperatures. Linear Ln(Sr)(3+)center dot center dot center dot O-i(2-) defect clusters and SrO shear planes characteristic of Ruddlesden Popper phases are found to be the most probable extended defects enabling the accommodation of excess oxygen in oxidized titanates with Sr(1-x)Ln(x)TiO(3+delta) cation stoichiometry. The presence of oxygen-rich local structures is shown to be strongly correlated with the faster redox kinetics and higher electrical conductivity critical for practical applications. Easy oxidation of reduced Sr(1-x)Ln(x)TiO(3+delta) (with electronic donor compensation) provide further evidence in favor of Ln(Sr)(3+)center dot center dot center dot O-i(2-) defect clusters as mechanism of excess oxygen accommodation.
publisher AMER CHEMICAL SOC
issn 0020-1669
year published 2016
volume 55
issue 10
beginning page 4836
ending page 4849
digital object identifier (doi) 10.1021/acs.inorgchem.6b00350
web of science category Chemistry, Inorganic & Nuclear
subject category Chemistry
unique article identifier WOS:000376144000018
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journal impact factor 4.700
5 year journal impact factor 4.513
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