Structural Regulation and Growth Mechanism of 3D-TiO2 Nanotubes

Abstract

The microstructure of titanium dioxide nanotubes significantly influences their properties. In this study, two types of three-dimensional titanium dioxide (3D-TiO2) nanotubes with different periodic structures were obtained by periodic pulse anodization of high-purity titanium sheets using discontinuous sawtooth waves under specific alternating-voltage (AV) and alternating-current (AC) conditions, and the inner pores of the nanotubes were both in a “gourd-like” structure. By adjusting the amplitude, period time, and duty cycle of the discontinuous sawtooth wave, the precise regulation of the structure of the 3D-TiO2 inner pore and outer tube can be achieved. This study demonstrates that the formation of “gourd-like” structure of the internal pore is mainly related to the migration rate of ions under low and high voltage/current and the dissolution rate of oxides on the inner wall of nanotubes. This study provides a new prospect for the application of 3D-TiO2 nanotubes, which have great potential for application in sensors, photocatalysis, and other fields.