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| Home > Publications database > Structure and dynamics at catalyst-ionomerinterfaces studied with molecular dynamics |
| Poster (After Call) | FZJ-2024-00916 |
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2023
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Please use a persistent id in citations: doi:10.34734/FZJ-2024-00916
Abstract: Catalyst-ionomer interfaces play a vital role for the performance of catalyst layers in polymerelectrolyte fuel cells. The catalyst layer harbors the electrochemically active sites at the catalyst surfaceand the ionomer embedded into the catalyst layer facilitates the efficient transport of protons.1,2 Thisinterface has a complex structure that can be characterized at multiple length scales, ranging from thenanoscale to the microscale. At nanoscale, the interface consists of individual catalyst particles that areembedded within the ionomer material.1,4 The catalyst particles are typically composed of platinum orplatinum-based alloys, and their size, shape, and surface morphology can have a significant impact on thecatalytic activity of the fuel cell. The ionomer material, which is typically a perfluorosulfonic acidpolymer, surrounds the catalyst particles and serves as a proton conductor and binder. In this work, weemploy atomistic molecular dynamics simulations for a model system of the nanoconfined water slabwithin the catalyst-ionomer interface to gain deeper insights into the impact of interfacial water-mediatedinteractions on its structural and dynamical properties. The proton concentration at the catalyst-ionomerinterface is directly influenced by the adsorption state and surface charge density of the metal-basedcatalyst1,2 as well as the structure and properties of the charged ionomer layer.3 Here, we explore the waterstructure and proton density distributions in the water slab as well as the dynamics of water molecules,hydronium ions, and anionic head groups as functions of interface structure and composition.References1. M.H. Eikerling, A.A Kulikovsky, Polymer Electrolyte Fuel Cells, CRC Press, Taylor & Francis Group, (2014).2. M. Eikerling, A.A. Kornyshev, and A.A. Kulikovsky, Physical Modeling of Cell Components, Cells and Stacks, inEncyclopedia of Electrochemistry, Vol. 5, ed. by D.D. Macdonald and P. Schmuki, ch. 8.2, 447-543, VCH-Wiley,Weinheim, (2007).3. A. Nouri-Khorasani, K. Malek, A. Malek, T. Mashio, D.P. Wilkinson, M.H. Eikerling, Catalysis Today. 262, (2016) 133-140.4. V. M. Fernández-Alvarez et al., J. Electrochem. Soc.,169 (2022), 024506
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