An Overview: Recent Development of Titanium Oxide Nanotubes as Photocatalyst for Dye Degradation

Table 3

Comparison of the most widely used synthesis methods for preparing TiO₂ nanotubes.

Synthesis method	Characteristics
Sol-gel transcription process	(a) Ordered arrays; (b) Advantages: the scale of nanotubes can be controlled by the applied template; (c) Disadvantages: the nanotubular structure can be damaged or destroyed during the after removal of the templates; raw materials used are expensive
Hydrothermal synthesis	(a) Random alignment; (b) Advantages: easy route to obtain nanotubes in relatively large amount; (c) Disadvantages: difficulty in producing uniform size of nanotubular; long reaction duration; and random distribution of nanostructured tubes
Electrochemical anodization	(a) Oriented arrays with high aspect ratio; (b) Advantages: self-organized anodic oxides in the form of nanotubular structures with almost perfect vertical, relatively simple alignment and can be adopted for large-scale industrial production; (c) Disadvantages: fabrication apparatuses are costly; massive organic waste will be produced after the anodization process