Tracking the Local Effect of Fluorine Self-Doping in Anodic TiO2 Nanotubes

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• 作者：Jun Li ; Changhai Liu ; Yifan Ye ; Junfa Zhu ; Suidong Wang ; Jinghua Guo ; Tsun-Kong Sham
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 3, 2016
• 年：2016
• 卷：120
• 期：8
• 页码：4623-4628
• 全文大小：398K
• ISSN：1932-7455

文摘

We report herein a study in which we reveal the role of F^– incorporated in the very anodic TiO₂ nanotubes prepared electrochemically from a Ti foil using a fluoride based electrolyte. X-ray absorption near edge structure (XANES), resonant X-ray emission spectroscopy (RXES), and X-ray photoelectron spectroscopy (XPS) have been used to examine the as-prepared and the annealed TiO₂ nanotubes. It is found that the additional electron resulting from the substitution of O^2– by self-doped F^– in the TiO₂ lattice is localized in the t_2g state. Consequently, a localized Ti³⁺ state can be tracked by a d–d energy loss peak with a constant energy of 1.6 eV in the RXES, in contrast to TiO₂ nanostructures where this peak is hardly noticeable when F^– is driven out of the lattice upon annealing.