Anisotropic Oxygen Diffusion Properties in Pr2NiO4+δ and Nd2NiO4+δ Single Crystals
The anisotropy of the oxygen anionic conductivity was measured for two mixed ionic electronic conducting (MIEC) oxides with the 2D K2NiF4-type structure, i.e., Nd2NiO4+δ and Pr2NiO4+δ, using high quality single crystals. Measurements of the oxygen diffusivity and surface exchange performed parallel...
Gespeichert in:
Veröffentlicht in: | Journal of physical chemistry. C 2013-12, Vol.117 (50), p.26466-26472 |
---|---|
Hauptverfasser: | , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | The anisotropy of the oxygen anionic conductivity was measured for two mixed ionic electronic conducting (MIEC) oxides with the 2D K2NiF4-type structure, i.e., Nd2NiO4+δ and Pr2NiO4+δ, using high quality single crystals. Measurements of the oxygen diffusivity and surface exchange performed parallel and perpendicularly to the [001] direction, from 450 to 700 °C, using the isotope exchange depth profile (IEDP) technique, combining 16O/18O exchange and secondary ion mass spectroscopy (SIMS) are reported. For both materials the diffusion is about 3 orders of magnitude higher along the (a,b)-plane compared to the perpendicular (c-axis) direction. These values are among the highest when compared to several state-of-the-art MIEC materials. The diffusion along the (a,b)-plane for Pr2NiO4+δ is higher than that of Nd2NiO4+δ due to a much lower diffusion activation energy (0.5 and 1.4 eV for Pr2NiO4+δ and Nd2NiO4+δ, respectively). A large anisotropy is also observed in the surface exchange coefficient (k*) values for both materials, with (a,b)-plane coefficients being 1 to 1.5 orders of magnitude larger than those for the c-axis. |
---|---|
ISSN: | 1932-7447 1932-7455 |
DOI: | 10.1021/jp409057k |