Facile Synthesis of Zinc Titanate Nanotubes via Reaction-byproduct Etching

A facile methodology to create zinc titanate nanotubes via reaction-byproduct etching is demonstrated. The chemical etching by the sol-gel reaction byproduct—hydrochloric acid (HCl) allows us to create the nanotube structure from the initial zinc oxide (ZnO)/titanium dioxide (TiO2) core/shell nanowires. We found that TiO2 shell layer plays crucial roles in the nanotube formation as a support layer to maintain their structure during etching and as a permeable layer for HCl and Zn ions in their diffusion processes.