Photocatalysis-Triggered Ion Rectification in Artificial Nanochannels Based on Chemically Modified Asymmetric TiO2 Nanotubes

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• 作者：Ziying Hu ; Qianqian Zhang ; Jun Gao ; Zhaoyue Liu ; Jin Zhai ; Lei Jiang
• 刊名：Langmuir
• 出版年：2013
• 出版时间：April 16, 2013
• 年：2013
• 卷：29
• 期：15
• 页码：4806-4812
• 全文大小：400K
• 年卷期：v.29,no.15(April 16, 2013)
• ISSN：1520-5827

文摘

Ion rectification is one of the important characteristics of biological ion channels. Inspired by the function of biological ion channels, creation of artificial nanochannels that show analogous ion rectification characteristics has attracted a great interest recently. Herein, we demonstrate a new type of artificial solid-state nanochannel with ion rectification characteristics. The creation of artificial nanochannels includes the formation of asymmetric TiO₂ nanotubes by electrochemical anodization of Ti metal, followed by chemical modification with octadecyltrimethoxysilane (OTS) molecules. The carboxylic groups are introduced onto the tip side of TiO₂ nanotubes via photocatalytic decomposition of OTS molecules by TiO₂ photocatalysis under ultraviolet light. When the radius of tip side of TiO₂ nanotubular channels is comparable to the thickness of electric double layer, the negatively charged surface in neutral electrolyte in combination with the asymmetric pore geometry contributes to the ion rectification characteristics. Compared with previous artificial nanochannels, our new type of artificial nanochannel is more facile to fabricate and behaves as a diode that rectifies the ion transport, which also shows some other potential applications, such as sensor and separation materials.