WEB Nanoporous Metals by Dealloying – Synthesis, in-situ Characterization and ApplicationsTuesday (22.09.2020) 14:45 - 15:00 Z: Special Symposia I Part of:
Dealloying is a synthesis routine for porous metals, in which the less noble component is removed from an alloy by selective etching. As a result, the remaining more noble component rearranges into a sponge-like bicontinuous network structure of pores and metallic network branches (ligaments). Depending on the material-specific surface diffusivity, dealloyed structures exhibit pore and ligament diameters ranging from less than five to several tens of nanometers, which in the following can be coarsened deliberately up to the micrometer range via thermal annealing.
By far, the most widely studied dealloyed material is nanoporous gold , but also a variety of other nanoporous metals is accessible via this process, such as platinum, palladium, copper or silver. Due to the small dimensionalities of the resulting structures, the physical properties may vary significantly from their bulk-sized counterparts. Dynamic insights to a spectrum of highly interesting processes in dealloyed materials can be gained by advanced in-situ methods: Resistometry can be used to study functional property tuning of the nanoporous metals  or the formation of self-assembled monolayers on the metallic ligaments . Also porosity evolution during the dealloying process was sucessfully investigated by this method . Actuation  and magnetic properties  are accessible via dilatometry and SQUID magnetometry respectively.
The potential fields of technological application for dealloyed, nanoporous metals are manifold, ranging from energy storage and (electro-)catalysis to sensing, electrochemical property tuning and biotechnology. As examples, the present contribution will focus on using nanoporous palladium as a model system for hydrogen loading  as well as surface-functionalized nanoporous gold as a carrier for enzyme immobilization .
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