Photocurrent Conversion in Anodized TiO2 Nanotube Arrays: Effect of the Water Content in Anodizing Solutions
详细信息 查看全文
- 作者：Lok-kun Tsui ; Takayuki Homma ; Giovanni Zangari
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：April 11, 2013
- 年：2013
- 卷：117
- 期：14
- 页码：6979-6989
- 全文大小：616K
- 年卷期：v.117,no.14(April 11, 2013)
- ISSN：1932-7455
文摘
The TiO2 nanotube system exhibits properties of interest in photoelectrochemical water splitting for hydrogen production, including high surface area and vectorial charge transport along the nanotube length. Changes in the anodizing electrolyte chemistry provide the means to control nanotube morphology as well as their length and width. Despite the large amount of work available on nanotube synthesis, however, a thorough assessment of the effect of anodization conditions on the photoelectrochemical performance is still unavailable. In this paper, we characterize TiO2 nanotubes produced by varying the water content of the organic anodization electrolyte and investigate the influence of the electrolyte on their photoelectrochemical performance. We find that the photocurrent efficiency of the nanotubes is optimized by using an 11 vol % water:ethylene glycol ratio. We also demonstrate that a double-anodization technique produces a cleaner surface, resulting in higher photon-to-current conversion efficiencies of up to 30% at 350 nm. Raman spectroscopy, X-ray diffraction, and electrochemical impedance studies support the notion that the variation in crystallinity as a function of water content is the main factor in determining the photocurrent efficiency of the nanotube system.