Table 1.

Comparison of available methods for TiO₂ nanotubes preparation

Fabrication method	Reaction conditions	Advantages	Disadvantages
Hydrothermal method	High pressure and high temperature.	High nanotube production rate.	Long reaction duration.
	Aqueous based solvent.	Easy to enhance the features of titanium nanotubes.	Difficult to achieve uniform size.
Solvothermal method	High pressure and high temperature.	Better control of the nanosize, crystal phase and narrow size distribution. Varieties of chosen organic solvent.	Critical reaction conditions.
	Organic solvent.		Long reaction time.
Electrochemical anodization method	5–50 V and 0.2–10 h under ambient conditions.	Ordered alignment with high aspect ratio.	Limited mass production.
	F–‐based buffered electrolytes and organic electrolytes, F–‐free electrolytes.	Controllable dimension of nanotubes by varying the voltage, electrolyte, pH and anodizing time.	Length distribution and separation of nanotubes over a large surface area is not well‐developed.
Template method	AAO, ZnO etc. as sacrificial template under specific conditions.	Controllable scale of nanotube by applied template.	Complicated fabrication process. Contamination or destroy of tubes may occur during fabrication process.
		Uniform size of nanotubes.