%0 journal article
%@ 1616-301X
%A Qi, Z., Vainio, U., Kornowski, A., Ritter, M., Weller, H., Jin, H., Weissmueller, J.

%D 2015
%J Advanced Functional Materials
%N 17
%P 2530-2536 
%R doi:10.1002/adfm.201404544
%T Porous Gold with a Nested-Network Architecture and Ultrafine Structure
%U https://doi.org/10.1002/adfm.201404544
17 
%X A preparation strategy is developed for monolithic samples of nanoporous gold with a hierarchical structure comprising two nested networks of solid “ligaments” on distinctly different structural length scales. The electrochemical dealloying protocol achieves a large retention of less noble element in a first corrosion step, thereby allowing an extra corrosion step which forms a separate structural hierarchy level. The beneficial impact of adding Pt to the Ag–Au master alloys that are more conventionally used in dealloying approaches to nanoporous gold is demonstrated. At ≈6 nm, the lower hierarchy level ligament size emerges extremely small. Furthermore, Pt favors the retention of Ag during the first dealloying step even when the master alloy has a high Au content. The high Au content reduces the corrosion-induced shrinkage, mitigating crack formation during preparation and favoring the formation of high-quality macroscopic (mm-sized) samples. The corrosion effectively carves out the nanoscale hierarchical ligament structure from the parent crystals tens of micrometers in size. This is revealed by X-ray as well as electron backscatter diffraction, which shows that the porous crystallites inherit the highly ordered, macroscopic crystal lattice structure of the master alloy.