Anatase-Selective Photoluminescence Spectroscopy of P25 TiO2 Nanoparticles: Different Effects of Oxygen Adsorption on the Band Bending of Anatase

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• 作者：Shiliang MaMatthew E. Reish ; Zhen Zhang ; Ian Harrison ; John T. Yates Jr.
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 19, 2017
• 年：2017
• 卷：121
• 期：2
• 页码：1263-1271
• 全文大小：524K
• ISSN：1932-7455

文摘

Photoluminescence (PL) spectroscopy was used to infer that oxygen adsorption changes the band bending of the anatase phase of TiO₂ within P25 nanopowder in different ways. On the one hand, oxygen can adsorb through irreversible reaction with defects which reduces the intrinsic upward band bending at the TiO₂ surface and results in increased PL emission. On the other hand, oxygen exposure also leads to molecular chemisorption that yields an outermost negative charge at the surface which increases the upward band bending of TiO₂ and decreases the PL emission. Since band bending plays an active role in directing charge carrier migration to the surface, the finding that oxygen adsorption can have two different, and quite opposite, effects on the band bending of TiO₂ provides a new perspective on how oxygen may influence photocatalytic reaction efficiencies.