Mixed conductivity, oxygen permeability and redox behavior of K{sub 2}NiF{sub 4}-type La{sub 2}Ni{sub 0.9}Fe{sub 0.1}O{sub 4+{delta}}

Journal Article · Sun Jun 15 00:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.03.019· OSTI ID:21128328

Tsipis, E V ^[1]; Naumovich, E N ^[2]; Thursfield, A ^[3]; Patrakeev, M V ^[4]; Kolotygin, V A ^[2]; Waerenborgh, J C ^[1]; Metcalfe, I S ^[3]

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1. Chemistry Department, ITN/CFMC-UL, Estrada Nacional 10, P-2686-953 Sacavem (Portugal)
2. Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)
3. School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)
4. Institute of Solid State Chemistry, UB RAS, 91 Pervomaiskaya Street, 620219 Ekaterinburg (Russian Federation)

The total conductivity and Seebeck coefficient of La{sub 2}Ni{sub 0.9}Fe{sub 0.1}O{sub 4+{delta}} with K{sub 2}NiF{sub 4}-type structure, studied in the oxygen partial pressure range from 10{sup -5} to 0.5 atm at 973-1223 K, were analyzed in combination with the steady-state oxygen permeability, oxygen non-stoichiometry and Moessbauer spectroscopy data in order to examine the electronic and ionic transport mechanisms. Doping of La{sub 2}NiO{sub 4+{delta}} with iron was found to promote hole localization on nickel cations due to the formation of stable Fe{sup 3+} states, although the electrical properties dominated by p-type electronic conduction under oxidizing conditions exhibit trends typical for both itinerant and localized behavior of the electronic sublattice. The segregation of metallic Ni on reduction, which occurs at oxygen chemical potentials close to the low-p(O{sub 2}) stability boundary of undoped lanthanum nickelate, is responsible for the high catalytic activity towards partial oxidation of methane by the lattice oxygen of La{sub 2}Ni{sub 0.9}Fe{sub 0.1}O{sub 4+{delta}} as revealed by thermogravimetry and temperature-programmed reduction in dry CH{sub 4}-He flow at 573-1173 K. A model for the oxygen permeation fluxes through dense La{sub 2}Ni{sub 0.9}Fe{sub 0.1}O{sub 4+{delta}} ceramics, limited by both bulk ionic conduction and surface exchange kinetics, was proposed and validated. - Graphical abstract: Oxygen permeation fluxes through iron-doped lanthanum nickelate ceramics.

• OSTI ID: 21128328
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 6; Other Information: DOI: 10.1016/j.jssc.2008.03.019; PII: S0022-4596(08)00162-X; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CERAMICS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
IRON COMPOUNDS
IRON IONS
LANTHANUM
LANTHANUM COMPOUNDS
MOESSBAUER EFFECT
NICKELATES
OXIDATION
OXIDES
OXYGEN
PARTIAL PRESSURE
PERMEABILITY
REDUCTION
SEGREGATION
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMAL GRAVIMETRIC ANALYSIS