TiO2 Anatase with a Bandgap in the Visible Region

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• 作者：Christian Dette ; Miguel A. P茅rez-Osorio ; Christopher S. Kley ; Paul Punke ; Christopher E. Patrick ; Peter Jacobson ; Feliciano Giustino ; Soon Jung Jung ; Klaus Kern
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：November 12, 2014
• 年：2014
• 卷：14
• 期：11
• 页码：6533-6538
• 全文大小：413K
• ISSN：1530-6992

文摘

TiO₂ anatase plays a central role in energy and environmental research. A major bottleneck toward developing artificial photosynthesis with TiO₂ is that it only absorbs ultraviolet light, owing to its large bandgap of 3.2 eV. If one could reduce the bandgap of anatase to the visible region, TiO₂-based photocatalysis could become a competitive clean energy source. Here, using scanning tunneling microscopy and spectroscopy in conjunction with density functional theory calculations, we report the discovery of a highly reactive titanium-terminated anatase surface with a reduced bandgap of less than 2 eV, stretching into the red portion of the solar spectrum. By tuning the surface preparation conditions, we can reversibly switch between the standard anatase surface and the newly discovered low bandgap surface phase. The identification of a TiO₂ anatase surface phase with a bandgap in the visible and high chemical reactivity has important implications for solar energy conversion, photocatalysis, and artificial photosynthesis.

Keywords:

Photocatalysis; TiO₂ anatase; titanium-terminated surface phase; bandgap reduction to the visible; scanning tunneling microscopy and spectroscopy; density functional theory