Oxygen isotope exchange in La sub(2)NiO sub(4 plus or minus ) delta

Oxygen surface exchange kinetics and diffusion have been studied by the isotope exchange method with gas phase equilibration using a static circulation experimental rig in the temperature range of 600-800 degree C and oxygen pressure range of 0.13-2.5 kPa. A novel model which takes into account dist...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2016-03, Vol.18 (13), p.9102-9111
Main Authors: Ananyev, M V, Tropin, E S, Eremin, V A, Farlenkov, A S, Smirnov, A S, Kolchugin, A A, Porotnikova, N M, Khodimchuk, A V, Berenov, A V, Kurumchin, EKh
Format: Article
Language:English
Subjects:
Balancing
Diffusion
Exchange
Gas phases
Isotopes
Mathematical models
Oxygen
Surface chemistry
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Summary:Oxygen surface exchange kinetics and diffusion have been studied by the isotope exchange method with gas phase equilibration using a static circulation experimental rig in the temperature range of 600-800 degree C and oxygen pressure range of 0.13-2.5 kPa. A novel model which takes into account distributions of the dissociative adsorption and incorporation rates has been developed. The rates of the elementary stages have been calculated. The rate-determining stages for a La sub(2)NiO sub(4 plus or minus ) delta polycrystalline specimen have been discussed. The diffusion activation energies calculated using the gas phase equilibration method (1.4 eV) differ significantly from those calculated using isotope exchange depth profiling (0.5-0.8 eV), which was attributed to the influence of different oxygen diffusion pathways.
ISSN:1463-9076
1463-9084
DOI:10.1039/c5cp05984d