Engineering the shape of one-dimensional metallic nanostructures via nanopore electrochemistry

The architecture of nanostructures is pivotal to determine material properties at the nanoscale, indicating the importance of harnessing sophisticated nanochemistry to elicit desirable material morphology with uniformity. The simplicity of template-assisted electrodeposition makes it a promising strategy for the fabrication of anisotropic nanomaterials. However, a challenge it faces is the complexity of the materials. This study presents a facile strategy and fabrication mechanism to synthesize nanotubes or nanocoils by selecting additives such as vanadyl ions and L-ascorbic acid. Vanadyl ions stick to the protonated anodized aluminum oxide surface, paving the way for electronic conduction. When a higher electrical field is applied, linear sweep voltammetry implies surface conduction mode is dominant in the spatially confined template. As L-ascorbic acid is included in the electrolyte, the nanostructure can be regulated from nanotubes to nanocoils. The nanocoils consist of numerous nanocrystalline primary particle considered as building blocks, and their relationship affects the final structures. The reaction product, vanadyl ascorbate, acts as a hurdle by partially hindering surface conduction and a helical modifier, inducing the formation of primary particle and their nanocoil assembly. Finally, a state diagram is provided to illustrate the diverse nanostructures at optimized applied current and additive ratio conditions.