Effect of Water Content on Structural and Photoelectrochemical Properties of Titania Nanotube Synthesized in Fluoride Ethylene Glycol Electrolyte

摘要

In this work, the effect of water content from < 1 to 100 vol% on the electrochemical anodization of titanium in ethylene glycol-based electrolyte was investigated. The samples were characterized using X-ray diffraction (XRD) and their dimensional change was monitored by field emission scanning electron microscopy (FE-SEM). It was found that the microstructure and morphology of TiO_2 varies dramatically with the water content. Nanotubes become less ordered with increasing water content up to 50 vol%. At 75 vol% water, only porous structure could be observed. Most importantly, at fixed applied voltage, smoother but relatively longer tubes can be grown with lower water content. Varying water content has no effect on the crystalline phase of the resulted nanotubes. However, the intensity of anatase (101) peak increases with increasing water content, indicating better crystallinity of samples. Nanotubes obtained in 50 vol% water exhibit the highest photoresponse when tested using linear sweep photovoltammetry due to enhanced microstructure and crystallinity.