Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session II

MM 20.2: Poster

Dienstag, 2. April 2019, 18:30–20:00, Poster C

Residual Silver in Nanoporous Gold prepared by Alloy Corrosion — Mareike Haensch¹, Matthias Graf², •Weijia Wang³, Alexei Nefedov³, Christof Woell³, and Gunther Wittstock¹ — ¹Karl von Ossietzky University of Oldenburg, Institute of Chemistry, Oldenburg, Germany — ²Hamburg University of Technology, Institute of Optical and Electronic Materials, Hamburg, Germany — ³Karlsruhe Institute of Technology, Institute of Functional Interfaces,Eggenstein-Leopoldshafen, Germany

Nanoporous gold (NPG), a nanoporous bulk material, finds applications in electrocatalysis, sensing and energy storage/conversion due to its large surface-to-volume ratio, good electrical conductivity, high catalytic activity and chemical/structural flexibility. Samples with homogeneous structures up to several mm in size can be obtained by dealloying a silver-gold alloy in concentrated nitric acid or by applying a potential program. However, the dealloying process is never complete. The dealloyed NPG contains a residual fraction of silver, which can affect its catalytic properties. A recent TEM study shows that the residual silver is present in silver-rich regions which are remnants of the parent alloy. The depth distribution of these regions is still under debate.XPS with variation of the excitation photon energy was used to identify depth-dependent distribution of residual silver. NPG samples which underwent different treatments were investigated. For all samples the silver enrichment was found at the surface, which is in agreement with previous studies.