Preparation and characterization of hierarchical nanostructures composed by CuO nanowires within directional microporous Cu

Thermal oxidation of Cu substrate in air is one of the most practical preparation methods for the preparation of CuO nanowires (NWs). Many efforts have been made to tune the CuO morphology, while there is quite rare report on the CuO morphology tuning by adjusting the copper substrate. In the present work, novel hierarchical porous Cu and the directional microporous Cu structures were prepared by etching Cu-Fe 3D printing precursors with or without ultrasonic treatment, respectively. Hierarchical nanostructures composed by CuO NWs within directional microporous Cu have been successfully prepared by thermal oxidizing a directional microporous Cu. The effect of the nanoporous Cu on the formation of the hierarchical nanostructures and the hierarchical nanostructures' morphology evolution were investigated. This work provides a novel insight into the preparation of hierarchical nanostructures by coupling nanostructures with the directional microporous structure.