Combining High Porosity with High Surface Area in Flexible Interconnected Nanowire Meshes for Hydrogen Generation and Beyond.

Nanostructured metals with large surface area have a great potential for multiple device applications. Although various metal architectures based on metal nanoligaments and nanowires are well known, they typically show a tradeoff between mechanical robustness, high surface area and high (macro)porosity, which, when combined, could significantly improve the performance of devices such as batteries, electrolyzers or sensors. In this work we rationally designed templated networks of interconnected metal nanowires, combining for the first time high porosity of metal foams, narrowly-distributed macropores and a very high surface area of nanoporous dealloyed metals. Thanks to their structural uniformity, the few-micron thick nanowire meshes are also remarkably flexible and durable. We show how the textural properties of the material can be precisely tuned to optimize the nanowire networks for applications in different devices. In an exemplary application in electrolytic production of hydrogen, thanks to its high surface area, a few-micron thick nanomesh outperformed a 300 times thicker nickel foam. Furthermore, thanks to its high porosity, the Pt-doped nanomesh surpassed a microporous Pt/C cloth, demonstrating benefits of the optimally designed nanowire structure for a simultaneous improvement and miniaturization of electrochemical devices. This work extends the potential of interconnected nanowires to multiple new research and industrial applications requiring highly porous and flexible conductive materials with high surface-to-volume ratio.