Single crystals in nature often demonstrate fascinating intricate porous morphologies rather than classical faceted surfaces. We are growing such crystals, drawing inspiration from biogenic porous single crystals. Here we show that nanoporous single crystals of gold can be grown with no need for any elaborate fabrication steps. These crystals are found to grow following solidification of a eutectic composition melt that forms as a result of the dewetting of nanometric thin films. We also present a kinetic model that shows how this nano-porous single-crystalline structure can be obtained, and which allows the potential size of the porous single crystal to be predicted. Retaining their single-crystalline nature is due to the fact that the full crystallization process is faster than the average period between two subsequent nucleation events. Our findings clearly demonstrate that it is possible to form singe crystalline nano porous metal crystals in a controlled manner. We also show that nanoporous single crystal prepared by eutectic composition demonstrate superior thermal stability as compared to their counterpart nanoporous gold prepared by dealloying, which is essential for catalysis.
Koifman Khristosov, L. Bloch, M. Burghammer, Y. Kauffmann, A. Katsman, B. Pokroy, "Sponge like nanoporous single crystals of gold", Nature Communications, 6:8841, 2015.
