Enhanced Photocatalytic Activity in Anatase/TiO2(B) Core−Shell Nanofiber

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• 作者：Wei Li ; Chang Liu ; Yaxin Zhou ; Yang Bai ; Xin Feng ; Zhuhong Yang ; Linghong Lu ; Xiaohua Lu ; Kwong-Yu Chan
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：December 25, 2008
• 年：2008
• 卷：112
• 期：51
• 页码：20539-20545
• 全文大小：405K
• 年卷期：v.112,no.51(December 25, 2008)
• ISSN：1932-7455

文摘

A bicrystalline titanium dioxide nanofiber with enhanced photocatalytic activity was synthesized from potassium titanate K₂Ti₂O₅ via ion exchange and calcination. The nanofiber has a core−shell crystalline structure with a thin TiO₂(B) phase sheathing the anatase core, as characterized by X-ray diffraction, Raman spectroscopy, and high-resolution transmission microscopy (HRTEM). From HRTEM and local electron diffraction patterns, the two crystalline phases form a coherent interface with the 0.34-nm spacing between the (102) planes of TiO₂(B) matching that between the anatase (101) lattice planes. The core−shell anatase/TiO₂(B) nanofiber shows enhanced photocatalytic activity in iodine oxidation reaction with a 20−50% increase in extent of reaction compared to either single-crystal anatase or single-crystal TiO₂(B) nanofibers. Anatase and TiO₂(B) have the same band gap value of 3.2 eV, while theoretical calculations show the conduction band (CB) and valence band (VB) energies in anatase are both lower than the corresponding CB and VB energies in TiO₂(B). The enhanced photocatalytic property may be due to enhanced and concerted charge mobility toward or away from the anatase/TiO₂(B) interface. The special structure−property relationship can provide a new strategy to design and fabricate efficient photocatalytic and photovoltaic materials.