Surface kinetics and bulk transport in La2Ni0.5Cu0.5O4+δ membranes from conductivity relaxation

This work reports conductivity relaxation measurements on both uncoated (1.2 mm thick) and coated (2.0 mm thick) La2Ni0.5Cu0.5O4+δ membranes in the temperature range between 550 and 850 °C and oxygen partial pressures from 0.01 to 1.0 atm. The results show that surface kinetics has a significant eff...

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Bibliographic Details
Published in:Journal of the European Ceramic Society 2023-02, Vol.43 (2), p.462-467
Main Authors: Li, Zuoan, Haugsrud, Reidar
Format: Article
Language:English
Subjects:
Conductivity relaxation
La2Ni0.5Cu 0.5 O4+δ
La2NiO4+δ
Oxygen diffusion
Surface exchange mechanisms
Surface modification
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Summary:This work reports conductivity relaxation measurements on both uncoated (1.2 mm thick) and coated (2.0 mm thick) La2Ni0.5Cu0.5O4+δ membranes in the temperature range between 550 and 850 °C and oxygen partial pressures from 0.01 to 1.0 atm. The results show that surface kinetics has a significant effect on the relaxation profiles, especially at low temperatures and should not be neglected when extracting transport parameters. Oxygen chemical diffusion and surface exchange coefficients have been determined by transient conductivity with surface modification. Higher activation energy of surface exchange compared to bulk diffusion is observed for La2Ni0.5Cu0.5O4+δ, similar to that for La2NiO4+δ. Based on the oxygen partial pressure dependence of the surface exchange coefficient, it has been revealed that oxygen dissociative adsorption rate-limits the surface exchange.
ISSN:0955-2219
1873-619X
DOI:10.1016/j.jeurceramsoc.2022.10.046