Band Structure Tuning of TiO2 for Enhanced Photoelectrochemical Water Splitting

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• 作者：Jiajun Wang ; Haifeng Sun ; Jing Huang ; Qunxiang Li ; Jinlong Yang
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 10, 2014
• 年：2014
• 卷：118
• 期：14
• 页码：7451-7457
• 全文大小：383K
• 年卷期：v.118,no.14(April 10, 2014)
• ISSN：1932-7455

文摘

Doping with anion and cation impurities is an effective approach to tune the photoelectrochemical properties of TiO₂. Here, we explore the Rh monodoping and (Rh + F) codoping effect on electronic structures and photocatalytic activities of anatase TiO₂ by performing extensive density functional theory calculations. Upon Rh monodoping, the band gap of TiO₂ can be effectively reduced. But this cationic dopant creates an unoccupied intermediate localized state within the band gap, which will act as photogenerated carrier recombination center, which reduces the photocatalytic efficiency. Fortunately, we find that the stable charge-compensated donor鈥揳cceptor pair (Rh + F) codoping in TiO₂ can effectively reduce the band gap by forming a delocalized intermediate band within the band gap. Moreover, the band edge alignment in the (Rh + F) codoped TiO₂ is desirable for water splitting. The calculated optical absorption curve of (Rh + F) codoped TiO₂ verifies that it has significantly improved visible light absorption. These findings imply that the (Rh + F) codoped TiO₂ is a promising visible light photocatalyst for water splitting.