Interaction of platinum-layered microparticles with Nafion film revealed by the acoustic dissociation method and
Akihisa Miyagawa1, Satoko Sugiyama2, Satoshi Fujita2
1Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-hiroshima, 739-8526, Japan.
Abstract:
Nafion is widely used in electrochemical systems, such as polymer electrolyte membrane fuel cells, owing to its high proton conductivity, chemical stability, and mechanical robustness. The interaction between Nafion and platinum (Pt) catalysts plays a critical role in determining the electrochemical performance; however, this interaction is strongly influenced by the solvent composition during Nafion film formation, and the underlying mechanism remains unclear. In this study, we investigated the interaction between Pt-layered microparticles and a Nafion-coated plate prepared with different solvent compositions (water/1-propanol = 75/25, 50/50, and 25/75 (v/v)) by combining an acoustic dissociation method with molecular dynamics (MD) simulations. The dissociation behavior of the particles depended on the interfacial interaction between Pt and Nafion, and stronger interactions were observed with increasing alcohol content. To elucidate the origin of this behavior, MD simulations were performed to evaluate the interfacial probability of the Nafion functional groups at the solution/vacuum interface. The results revealed that the probability of sulfonate group exposure at the interface increased with increasing alcohol ratio. These findings indicate that the enhanced exposure of sulfonate groups at higher alcohol contents leads to stronger interactions between Pt and Nafion.
