Origin of Photocatalytic Activity of Nitrogen-Doped TiO2 Nanobelts

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• 作者：Jin Wang ; De Nyago Tafen ; James P. Lewis ; Zhanglian Hong ; Ayyakkannu Manivannan ; Mingjia Zhi ; Ming Li ; Nianqiang Wu
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：September 2, 2009
• 年：2009
• 卷：131
• 期：34
• 页码：12290-12297
• 全文大小：329K
• 年卷期：v.131,no.34(September 2, 2009)
• ISSN：1520-5126

文摘

Experiments combined with the density functional theory (DFT) calculation have been performed to understand the underlying photocatalysis mechanism of the nitrogen-doped titania nanobelts. Nitrogen-doped anatase titania nanobelts are prepared via hydrothermal processing and subsequent heat treatment in NH₃. Both the nitrogen content and the oxygen vacancy concentration increase with increasing the NH₃ treatment temperature. Nitrogen doping leads to an add-on shoulder on the edge of the valence band, the localized N 2p levels above the valence band maximum, and the 3d states of Ti³⁺ below the conduction band, which is confirmed by DFT calculation and X-ray photoelectron spectroscopy (XPS) measurement. Extension of the light absorption from the ultraviolet (UV) region to the visible-light region arises from the N 2p levels near the valence band and from the color centers induced by the oxygen vacancies and the Ti³⁺ species. Nitrogen doping allows visible-light-responsive photocatalytic activity but lowers UV-light-responsive photocatalytic activity. The visible-light photocatalytic activity originates from the N 2p levels near the valence band. The oxygen vacancies and the associated Ti³⁺ species act as the recombination centers for the photoinduced electrons and holes. They reduce the photocatalytic activity although they contribute to the visible light absorbance.