Titanium dioxide nanotube arrays fabricated by anodizing processes

Extended and oriented nanostructures are desirable for many applications, but direct fabrication of complex nanostructures with well-aligned morphology, orientation, and surface architectures remains a significant challenge. Here, we study a simple electrochemical anodizing process to fabricate arrays of titanium (Ti) nanotubes without the use of a template. The nanotubes are formed perpendicular to the metal substrate as an open-ended array in a continuous, well-aligned conformation. The hole size and separation have been found to be dependent on the anodizing voltage and on anodizing time. It was found that the nanotube deposition process had a low faradaic efficiency, and a large fraction of the Ti was transformed into soluble species in the anodizing bath. The Ti O2 nanotubes have uniform diameters that make them suitable for electrochemical intercalation hosts for Li+ ions and other applications.