Following the Reduction of Oxygen on TiO2 Anatase (101) Step by Step

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• 作者：Martin Setvin ; Ulrich Aschauer ; Jan Hulva ; Thomas Simschitz ; Benjamin Daniel ; Michael Schmid ; Annabella Selloni ; Ulrike Diebold
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：138
• 期：30
• 页码：9565-9571
• 全文大小：502K
• 年卷期：0
• ISSN：1520-5126

文摘

We have investigated the reaction between O₂ and H₂O, coadsorbed on the (101) surface of a reduced TiO₂ anatase single crystal by scanning tunneling microscopy, density functional theory, temperature-programmed desorption, and X-ray photoelectron spectroscopy. While water adsorbs molecularly on the anatase (101) surface, the reaction with O₂ results in water dissociation and formation of terminal OH groups. We show that these terminal OHs are the final and stable reaction product on reduced anatase. We identify OOH as a metastable intermediate in the reaction. The water dissociation reaction runs as long as the surface can transfer enough electrons to the adsorbed species; the energy balance and activation barriers for the individual reaction steps are discussed, depending on the number of electrons available. Our results indicate that the presence of donor dopants can significantly reduce activation barriers for oxygen reduction on anatase.