What happens if anodic TiO2 nanotubes are soaked in H3PO4 at room temperature for a long time?

Abstract

We have found that anodized amorphous TiO2 nanotubes can be transformed into rutile phase TiO2, resulting in the formation of a flower-like structure, when soaked in H3PO4 solution at room temperature for 2–4 days. The presence of PO43− ions in the soaking solution is believed to play a key role in the formation of the flower-like TiO2 structure. The resulting TiO2 flower-like material can be used as a binder-free electrode and exhibits obvious redox activity in AlCl3 solution and superior supercapacitive performance compared to conventional TiO2 nanotubes. The presented technique offers a simple, scalable, energy-saving, and cost-effective way to tailor the morphology and properties of anodized TiO2 nanotubes for different applications.