Silver-rich clusters in nanoporous gold

High-resolution elemental mapping in a transmission electron microscope shows that the residual silver in dealloying-made nanoporous gold (NPG) is aggregated in nanoscale clusters. Kinetic Monte Carlo simulation confirms that these regions are buried relics of the master alloy that have never been exposed to corrosion. The surface of as-dealloyed NPG is covered by at least one atomic monolayer of nearly pure gold. The preferential location of silver in the bulk is relevant when interfaces control the material's function, as in catalysis and sensing. Annealing in air homogenizes the alloy by surface diffusion. [GRAPHICS] . IMPACT STATEMENT The residual silver which is typically found in nanoporous gold made by dealloying is localized in clusters that are relics of the original master alloy which have evaded corrosion.