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@ARTICLE{Mutter:893309,
author = {Mutter, Daniel and Urban, Daniel F. and Elsässer,
Christian and Schierholz, Roland and Heuer, Sabrina and
Ohlerth, Thorsten and Kungl, Hans and Eichel, Rüdiger-A.},
title = {{D}efects and phase formation in non-stoichiometric
{L}a{F}e{O}$_3$: a combined theoretical and experimental
study},
journal = {Chemistry of materials},
volume = {33},
number = {24},
issn = {0897-4756},
address = {Washington, DC},
publisher = {American Chemical Society},
reportid = {FZJ-2021-02683},
pages = {25},
year = {2021},
abstract = {The defect chemistry of perovskite compounds is directly
related to the stoichiometry and to the valence states of
the transition metal ions. Such relations are of high
interest as they offer the possibility to influence the
catalytic activity of perovskites for the application in
solid-oxide fuel- and electrolyser cells. Combining
theoretical and experimental approaches, we explore the
feasibility of actively manipulating the valence state of Fe
and the concentration of point defects by synthesizing
non-stoichiometric LaFeO$_3$ (LFO). In the theoretical part,
formation energies and concentrations of point defects were
determined as a function of processing conditions by
first-principles DFT+U calculations. Based on the DFT+U
results, significant compositional deviations from
stoichiometric LFO cannot be expected by providing rich or
poor conditions of the oxidic precursor compounds
(Fe$_2$O$_3$ and La$_2$O$_3$) in a solid-state processing
route. In the experimental part, LFO was synthesized with a
targeted La-site deficiency. We analyze the resulting phases
in detail by X-ray diffraction and dedicated microscopy
methods, namely scanning electron microscopy (SEM) and
(scanning) transmission electron Microscopy ((S)TEM) in
combination with energy dispersive X-ray spectroscopy (EDS)
and electron energy-loss spectrometry (EELS). Instead of a
variation of the La/Fe ratio, a mixture of two phases,
Fe$_2$O$_3$/LaFeO$_3$, was observed resulting in an
invariant charge state of Fe, which is in line with the
theoretical results. We discuss our findings with respect to
partly differing assumptions made in previously published
studies on this material system.},
cin = {IEK-9},
ddc = {540},
cid = {I:(DE-Juel1)IEK-9-20110218},
pnm = {1223 - Batteries in Application (POF4-122) / HITEC -
Helmholtz Interdisciplinary Doctoral Training in Energy and
Climate Research (HITEC) (HITEC-20170406)},
pid = {G:(DE-HGF)POF4-1223 / G:(DE-Juel1)HITEC-20170406},
typ = {PUB:(DE-HGF)16},
eprint = {2106.09571},
howpublished = {arXiv:2106.09571},
archivePrefix = {arXiv},
SLACcitation = {$\%\%CITATION$ = $arXiv:2106.09571;\%\%$},
UT = {WOS:000731152800001},
doi = {10.1021/acs.chemmater.1c02106},
url = {https://juser.fz-juelich.de/record/893309},
}