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MM: Fachverband Metall- und Materialphysik
MM 39: Hydrogen in Materials II
MM 39.2: Vortrag
Freitag, 13. März 2026, 10:30–10:45, SCH/A215
Interfacial kinetics of hydrogen absorption in nanoporous palladium — •Seoyun Sohn1,2, Nora Brunkhorst2, Jürgen Markmann2,1, and Jörg Weissmüller1,2 — 1Institute of Materials Physics and Technology, Hamburg University of Technology, 21073 Hamburg, Germany — 2Institute of Hydrogen Technology, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
Sorption of hydrogen at metal surfaces is a key process controlling energy-conversion reactions, electrocatalysis, and battery operation. To focus on the interfacial sorption step and minimize bulk-transport contributions, we explore nanoporous (np) Pd as a model system, following the charging/discharging kinetics during electrochemical charging or exposure to H2 gas at controlled partial pressure. Our observations point towards thermally activated transition across an internal barrier–between adsorbed and absorbed H–as the rate limiting step, and they exhibit anomalous kinetics, where absorption or desorption rates do not monotonously decrease with time. The command critiques the applicability of the Butler-Volmer equation–as a classic approach to the kinetics–and we advertise an alternative kinetic rate law that resolves the problematic issues of the classic approach. We show that the new rate law explains important features of the observations, specifically when admitting for a coherent initiation of the phase change.
Keywords: hydrogen; palladium; sorption; nanoporous; kinetics