000912054 001__ 912054
000912054 005__ 20240712113240.0
000912054 0247_ $$2Handle$$a2128/33227
000912054 0247_ $$2URN$$aurn:nbn:de:0001-2023013169
000912054 020__ $$a978-3-95806-663-2
000912054 037__ $$aFZJ-2022-05281
000912054 1001_ $$0P:(DE-Juel1)165352$$aKaraca, Ali$$b0$$eCorresponding author
000912054 245__ $$aEignung von nickelhaltigen Katalysatorsystemen in sauren Medien zur Nutzung im Betrieb von Brennstoffzellen$$f- 2022-08-30
000912054 260__ $$aJülich$$bForschungszentrum Jülich GmbH Zentralbibliothek, Verlag$$c2022
000912054 300__ $$aiv, 249
000912054 3367_ $$2DataCite$$aOutput Types/Dissertation
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000912054 3367_ $$2ORCID$$aDISSERTATION
000912054 3367_ $$2BibTeX$$aPHDTHESIS
000912054 3367_ $$02$$2EndNote$$aThesis
000912054 3367_ $$0PUB:(DE-HGF)11$$2PUB:(DE-HGF)$$aDissertation / PhD Thesis$$bphd$$mphd$$s1671616090_30090
000912054 3367_ $$2DRIVER$$adoctoralThesis
000912054 4900_ $$aSchriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment$$v594
000912054 502__ $$aDissertation, RWTH Aachen University, 2022$$bDissertation$$cRWTH Aachen University$$d2022
000912054 520__ $$aCatalysts for the oxygen reduction reaction in fuel cells are more favorable when platinum is replaced by alternative materials such as non-precious metals and their catalytic activity is increased. This work addresses a reduction of platinum in the cathode of a direct methanol fuel cell by using nickel. Two approaches are investigated: platinum-nickel alloys and core-shell structures. Automated ultrasonic spraycoating was used to produce mechanically stable electrodes with reproducible electrochemical properties. In addition, whole catalyst-coated membranes (CCMs) were integrally fabricated using ultrasonic spray technology. The ionomer to carbon ratio (I/C) in the electrode was shown to have a significant effect on the electrochemically active surface area (44.7 (I/C 0.87) and 53.0 m2 g-1 (I/C 0.5)). Core-shell catalysts have lower powerdensities than the alloys. Long-term stability of at least 1000 hours of operation with increase in performance is given for both. Both catalyst types experience significant nickel discharge from the surface of the particles, which explains the performance increases. Both alloy and core-shell catalysts exhibit increased methanol tolerance compared to commercial platinum particles. In addition, fabrication of membraneelectrode assemblies has been demonstrated as an integral process by ultrasonic spraying of the electrode and membrane. Thermal modification could be used toimprove the conductivity of the membranes but is not practical in real processes and results in performance losses under the selected conditions. Modification of the membranes with high-boiling solvents also does not result in any improvements. Trace amounts or degradation products of the solvents (DMAc, DMF) lead to membrane poisoning and higher ionic resistivities (0.18 untreated, 0.30 with DMAc and 2.18 Ω cm2 with DMF). Membranes with very good protonic conductivity and low permeations are obtained using graphene oxide as an additive. Thin membranes (20 30 μm) with graphene oxide have up to 20% better protonic conductivity and 50% lower hydrogen permeation. However, the methanol permeation does not decrease. In the long term, the results and findings obtained in this work can lead to a significant reduction in theplatinum content in fuel cells, a simplification of the manufacturing process and an improvement in the properties in terms of permeation, performance, and stability of the membrane-electrode assemblies
000912054 536__ $$0G:(DE-HGF)POF4-1231$$a1231 - Electrochemistry for Hydrogen (POF4-123)$$cPOF4-123$$fPOF IV$$x0
000912054 8564_ $$uhttps://juser.fz-juelich.de/record/912054/files/Energie_Umwelt_594.pdf$$yOpenAccess
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000912054 915__ $$0LIC:(DE-HGF)CCBY4$$2HGFVOC$$aCreative Commons Attribution CC BY 4.0
000912054 9141_ $$y2022
000912054 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)165352$$aForschungszentrum Jülich$$b0$$kFZJ
000912054 9131_ $$0G:(DE-HGF)POF4-123$$1G:(DE-HGF)POF4-120$$2G:(DE-HGF)POF4-100$$3G:(DE-HGF)POF4$$4G:(DE-HGF)POF$$9G:(DE-HGF)POF4-1231$$aDE-HGF$$bForschungsbereich Energie$$lMaterialien und Technologien für die Energiewende (MTET)$$vChemische Energieträger$$x0
000912054 920__ $$lyes
000912054 9201_ $$0I:(DE-Juel1)IEK-14-20191129$$kIEK-14$$lElektrochemische Verfahrenstechnik$$x0
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000912054 981__ $$aI:(DE-Juel1)IET-4-20191129