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@PHDTHESIS{Berger:1020331,
author = {Berger, Maike},
othercontributors = {Palkovits, Regina and Liauw, Marcellus},
title = {{E}isen-{N}ickel-basierte {D}oppelschichthydroxide als
{E}lektrokatalysatoren für die alkalische
{W}asserelektrolyse},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-08904},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, RWTH Aachen University, 2025},
abstract = {Green hydrogen represents a promising energy carrier for
the large-scale storage of renewable energy and is therefore
the focus of current research. The use of highly active,
precious metal-free catalysts is an important contribution
to increasing the competitiveness of green hydrogen. This
research focuses on the study and optimization of NiFe-based
layered double hydroxides as electrocatalysts in the oxygen
evolution reaction, which show high potential due to their
cost efficiency, high availability, and promising catalytic
performance. To improve catalytic performance, various
approaches were chosen to optimize the material, and
promising systems were kinetically studied. Initially,
alongside iron and nickel, other 3d-transition metals were
incorporated. The resulting increase in activity was
attributed to the enhanced conductivity due to a changed
electronic structure of the LDH layers. Another property of
the material, the ability to incorporate various anions into
the interlayers, was utilized to positively influence
performance. Anions were able to increase catalytic activity
by affecting the interlayer distance and charge transfer
resistance. Simple anions were first chosen for an initial
investigation, and a detailed kinetic analysis was carried
out using electrochemical steady-state techniques. Based on
the results, the mechanism of OER catalysis on NiFe LDH was
identified, as well as the adsorption conditions of the
intermediates, and rate-determining steps were calculated.
These kinetic findings were further confirmed in another
series of anion exchanges based on inorganic and organic
borates. While organic borates, due to their aromaticity and
the accompanying greater delocalization of negative charge,
had an activity-reducing effect on OER performance, the
incorporation of B(OH)4−, due to its strong Lewis
basicity, resulted in increased activity. As another class
of anions, sulfur-based anions were chosen and successfully
incorporated into the interlayer. The materials exhibited
significant agglomeration regardless of the electrode
material. A thorough activity analysis was performed, and
dependencies of the activity on interlayer distance, pKs
value of the conjugate acid, and redox reactivity were
examined. Finally, a new manufacturing method for this
application, co-precipitation in an inverse microemulsion,
was tested, aimed at producing nanoscale NiFe LDHs with a
narrow particle size distribution. It was found that smaller
crystallites led to improved OER activity. Smaller
crystallites potentially lead to more grain boundaries, and
thus a modified electronic surface structure, which can be
beneficial for OER performance.},
cin = {155310 / 150000},
ddc = {540},
cid = {$I:(DE-82)155310_20140620$ / $I:(DE-82)150000_20140620$},
pnm = {BMBF 03HY109B - $Verbundvorhaben_H2Giga_QT1.5_AlFaKat:$
Neuartige Katalysatoren für AEM-WE
Membran-Elektroden-Einheiten - Teilvorhaben: Qualifizierung
von Materialien für die Fallbeschichtung (03HY109B)},
pid = {G:(BMBF)03HY109B},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2025-08904},
url = {https://publications.rwth-aachen.de/record/1020331},
}
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