TiO₂ nanotubes

Anatase titanium dioxide nanopowders are dispersed in sodium hydroxide solution (15 mL, 10 M) under magnetic stirring and transferred to a Teflon lined autoclave under magnetic stirring, 130 °C of hydrothermal reaction for 24 hours.

The precipitates are washed to pH approximately equal to 9 and washed with nitric acid (0.1 M) 3 times (hydrogen ion exchange process), then rinsed with deionized water until pH is neutral.

After filtering (centrifuge) and drying, the product is heated in a tube

furnace and kept at 400 °C for 6 hours

• Electrolyte solution : 0.3 wt.% NH₄F , 2 % deionized water and 98 % ethylene glycol.

• A clean titanium foil is used as the anode and (graphite rod/Pt foil) is used as the counter electrode.

• A constant voltage of 30 V is applied at room temperature.

• The as-grown NT arrays on the Ti foil is calcined in air at 500 ℃ for 2 h.