Nanotubes fabricated by anodizing processes for advanced material application

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 report a successful robust fabrication of titanium (Ti) and zirconium (Zr) oxide nanotubes by a simple electrochemical anodizing process without the use of any template. The nanotubes formed perpendicular to the metal substrates and had an open ended array of continuous, well-aligned conformation with various hole sizes, depending upon applied anodizing voltages and times. Both the TiO ₂ and ZrO ₂ nanotubes have a uniform diameter which may make them suitable for chemical sensing, catalysis, optical emission and nanoelectrode assembly for batteries and electrochemistry.