Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7744223 | Solid State Ionics | 2018 | 10 Pages |
Abstract
The influence of simultaneous Cr- and Si-poisoning on the oxygen exchange kinetics of La2NiO4+δ was studied at 800â¯Â°C in dry and humid O2/Ar atmospheres over a period of 4000â¯h by means of dc-conductivity relaxation measurements. Chemical and morphological changes of the La2NiO4+δ surface exposed to increasingly harsh ambient conditions were investigated using X-ray photoelectron spectroscopy (XPS) depth profiling, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDXS) and high-resolution scanning transmission electron microscopy with energy dispersive X-ray and electron energy loss spectroscopy (HR-STEM EDXS/EELS). In the presence of Cr/Si-sources and under dry conditions, La2NiO4+δ shows good stability for more than 1000â¯h. However, as soon as humidity is introduced into the system a strong decline of the oxygen exchange activity is observed. Post-test analyses reveal newly formed partially blocking Cr- and Si-rich secondary phases on the surface of La2NiO4+δ which impede the surface exchange of oxygen.
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Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
N. Schrödl, A. Egger, C. Gspan, T. Höschen, F. Hofer, W. Sitte,