Atomistic study of a CaTiO3-based mixed conductor: Defects, nanoscale clusters, and oxide-ion migration
authors Mather, GC; Islam, MS; Figueiredo, FM
nationality International
journal ADVANCED FUNCTIONAL MATERIALS
keywords DOPANT SITE-SELECTIVITY; PEROVSKITE-TYPE OXIDES; CALCIUM TITANATE; COMPUTER-SIMULATION; OXYGEN VACANCIES; CAFE(X)TI1-XO3-X/2 PEROVSKITES; NEUTRON-DIFFRACTION; PHASE-TRANSITIONS; SHORT-RANGE; DIFFUSION
abstract Mixed oxide-ion and electronic conductivity can be exploited in dense ceramic membranes for controlled oxygen separation as a means of producing pure oxygen or integrating with catalytic oxidation. Atomistic simulation has been used to probe the energetics of defects dopant-vacancy association, nanoscale cluster formation, and oxide-ion transport in mixed-conducting CaTiO3. The most favorable energetics for trivalent dopant substitution on the Ti site are found for Mn3+ and Sc3+. Dopant-vacancy association is predicted for pair clusters and neutral trimers. Low binding energies are found for Sc3+ in accordance with the high oxide-ion conductivity of Sc-doped CaTiO3. The preferred location for Fe4+ is in a hexacoordinated site, which supports experimental evidence that Fe4+ promotes the termination of defect chains and increases disorder. A higher oxide-ion migration energy for a vacancy mechanism is predicted along a pathway adjacent to an Fe3+ ion rather than Fe4+ and Ti4+, consistent with the higher observed activation energies for ionic transport in reduced CaTi(Fe)O3-delta.
publisher WILEY-V C H VERLAG GMBH
issn 1616-301X
year published 2007
volume 17
issue 6
beginning page 905
ending page 912
digital object identifier (doi) 10.1002/adfm.200600632
web of science category Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter
subject category Chemistry; Science & Technology - Other Topics; Materials Science; Physics
unique article identifier WOS:000246414100007
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journal impact factor 13.325
5 year journal impact factor 13.274
category normalized journal impact factor percentile 94.154
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