Reduction-Induced Decomposition of Powder Compacts for the Controllable Fabrication of Monolithic Nanoporous Metals

Abstract

Nanoporous (NP) metals offer large surface areas in monolithic form factors, a combination desired in electrocatalysis, batteries, sensing, and actuation. Their fabrication, via either the conventional method of dealloying or emerging methods such as reduction-induced decomposition (RID), requires homogeneous bulk precursors, whose preparation remains a barrier to the broader applications. This work explores compound powder as one of the simplest forms of precursor. With compaction and sintering, we utilize a range of precursors to generalize RID for the fabrication of monolithic NP Ag, Cu, Pb, and Sn with uniform ligament sizes of 50 – 500 nm and porosity in the range of 40 – 90% with well controlled shapes and dimensions. The compaction pressure, the sintering temperature, and the powder size are related to the porosity, the structural hierarchy, and the length scales, delivering functional NP metals of highly controllable properties.

Keywords: Nanoporous metal, hierarchical structure, dealloying, electrode