Bulk Nanostructuring of Janus‐Type Metal Electrodes

Abstract

Face-dependent bulk nanostructuring of Cu metal electrodes is reported, leading to Janus-type electrodes where one face features Cu(OH)2 nanowires while the other face is decorated with CuO nanoflowers. Thermal conversion into CuxO nanowires/nanoflowers as well as chemical reduction to elemental Cu nanowires/nanoflowers demonstrate the versatility of the approach. Initial electrocatalytic studies show the electrochemical reactivity of the composite electrodes.The stable deposition of reactive nanostructures on metal electrodes is a key process for modern technologies including energy conversion/ storage, electrocatalysis or sensing. Here a facile, scalable route is reported, which allows the bulk nanostructuring of copper foam electrodes with metal, metal oxide or metal hydroxide nanostructures. A concentration-gradient driven synthetic approach enables the fabrication of Janus-type electrodes where one face features Cu(OH)2 nanowires, while the other face features CuO nanoflowers. Thermal or chemical conversion of the nanostructured surfaces into copper oxide or copper metal is possible whilst retaining the respective nanostructure morphologies. As proof of concept, the functionalized electrodes are promising in electrocatalytic water oxidation and water reduction reactions.