Structure and conductivity of rutile niobium iron titanate

The structure and electrical conductivity of the solid solution FexTi1−2xNbxO2-δ (x=0.1, 0.2, 0.3) have been investigated. A solid solution with the rutile structure is observed, along with an increase in unit cell volume with increasing substitution. The conductivity in 5% H2/Ar reduced with increa...

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Bibliographic Details
Published in:Solid state ionics 2013-04, Vol.236, p.48-53
Main Authors: Cowin, Peter I., Petit, Christophe T.G., Lan, Rong, Schaschke, Carl J., Tao, Shanwen
Format: Article
Language:English
Subjects:
Anode
Conductivity
Doping
Electrical resistivity
Iron niobium titanate
Reduction
Resistivity
Rutile
Solid oxide fuel cell
Solid solutions
Titanates
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Summary:The structure and electrical conductivity of the solid solution FexTi1−2xNbxO2-δ (x=0.1, 0.2, 0.3) have been investigated. A solid solution with the rutile structure is observed, along with an increase in unit cell volume with increasing substitution. The conductivity in 5% H2/Ar reduced with increasing doping levels, reaching a maximum of 2.67Scm−1 at 700°C for Fe0.1Ti0.8Nb0.1O2-δ. None of the compounds in this series were redox stable at 700°C in 5% H2/Ar, with increasing amounts of a haematite secondary phase observed with increased doping levels. Reduction at 900°C in 5% H2/Ar caused a significant increase in conductivity (8.34Scm−1 in 5%H2/Ar) at 700°C, suggesting that only partial reduction occurs at lower temperatures. The lack of redox stability and relatively low conductivities of these materials makes them unsuitable as a component of composite anode for IT-SOFC. ► A rutile solid solution FexTi1-2xNbxO2-δ (x
ISSN:0167-2738
1872-7689
DOI:10.1016/j.ssi.2013.01.017