Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 1: Topical Session Nanoporous Functional Materials I

MM 1.1: Hauptvortrag

Montag, 23. März 2009, 10:15–10:45, IFW A

Fabrication and Properties of Nanoporous Metals by Electrochemical Dealloying — •Jonah Erlebacher — Johns Hopkins University, Baltimore, MD

Dealloying, the electrochemical selective dissolution of a multi-component alloy, is an intrinsically nanoscale phenomena that under the right conditions leads to the formation of highly porous metals due to an atomic-scale competition between electrochemical dissolution and crystalline surface diffusion of the remaining components. Recent attention in this area is focused toward practical application of dealloying to form "nanoporous" metals with pore sizes less than 10 nm possessing ultra-high surface areas. Nanoporous metals formed by dealloying are microstructurally contiguous porous single crystal networks, and not fragile sintered agglomerations of nanoparticles. For this reason, they are finding many new applications in sensing and catalysis.

In this presentation, we will describe the evolution of the beautiful nanoporous microstructure of dealloyed metals and their applications in a variety of contexts. We will also discuss the use of a minority ternary component in the alloy precursors that stymie surface mobility along step edges, stabilizing the nanoporous morphology during dealloying, and the use of electrochemical tricks to control the surface composition of the nanoporous metal. Finally, we will discuss the development of new nanoporous metals that exhibit remarkable catalytic activity, particularly toward chemical reactions important to energy technologies, such as oxygen reduction in fuel cells