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MM: Fachverband Metall- und Materialphysik
MM 23: Topical Session: Hydrogen in Materials: from Storage to Embrittlement III
MM 23.2: Vortrag
Dienstag, 19. März 2024, 12:15–12:30, C 130
Hydrogen sorption kinetics in nanoporous palladium — •Seoyun Sohn1, Jürgen Markmann1,2, Shan Shi3,1, and Jörg Weissmüller2,1 — 1Institute of Materials Mechanics, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany — 2Institute of Materials Physics and Technology, Hamburg University of Technology, 21073 Hamburg, Germany — 3Research Group of Integrated Metallic Nanomaterials Systems, Hamburg University of Technology, 21073 Hamburg, Germany
Palladium is one of the most intensely studied model materials for hydrogen in metals. The fabrication of nanoporous Pd by dealloying results in a macroscopic sample with a nanoscale network structure, which can efficiently absorb hydrogen due to its large specific surface area and short diffusion paths. The material has been reported to undergo more than 1000 loading/unloading cycles through the α/α′ phase transformation without degradation. In this work, the ligament size of nanoporous Pd is tuned from 20 to 500 nm with the aim of understanding the role of the geometry on the charging kinetics and ultimately on the phase transformation mechanism. The hydrogen ad/absorption and desorption kinetics are studied using electrochemical impedance spectroscopy and potential jump tests. The results suggest a controlling role of the interfacial injection process and an extremely small Damköhler number. This outcome will offer guidance to improve charging kinetics for functional performance.
Keywords: nanoporous; palladium; hydrogen; kinetics; phase transformation