Direct Observation of Oxygen Vacancy Self‐Healing on TiO2 Photocatalysts for Solar Water Splitting. (29th August 2019)

• Record Type: Journal Article
• Authors: Zhang, Yajun; Xu, Zhongfei; Li, Guiyu; Huang, Xiaojuan; Hao, Weichang; Bi, Yingpu
• Is Part Of: Angewandte Chemie. Volume 131:Number 40(2019)
• Page Start: 14367
• Page End: 14371
• Publication Date: 2019-08-29
• Subjects: Photokatalyse -- Sauerstoffvakanzen -- Selbstheilung -- TiO2 -- Wasserstofferzeugung; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201907954
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Oxygen vacancy (Vo) on transition metal oxides plays a crucial role in determining their chemical/physical properties. Conversely, the capability to directly detect the changing process of oxygen vacancies (Vos) will be important to realize their full potentials in the related fields. Herein, with a novel synchronous illumination X‐ray photoelectron spectroscopy (SI‐XPS) technique, we found that the surface Vos (surf‐Vos) exhibit a strong selectivity for binding with the water molecules, and sequentially capture an oxygen atom to achieve the anisotropic self‐healing of surface lattice oxygen. After this self‐healing process, the survived subsurface Vos (sub‐Vos) promote the charge excitation from Ti to O atoms due to the enriched electron located on low‐coordinated Ti sites. However, the excessive sub‐Vos would block the charge separation and transfer to TiO2 surfaces resulted from the destroyed atomic structures. These findings open a new pathway to explore the dynamic changes of Vos and their roles on catalytic properties, not only in metal oxides, but in crystalline materials more generally. Abstract : Selbstheilende Sauerstoffvakanzen (Vo) auf TiO2 ‐Photokatalysatoren in der Wasserspaltungsreaktion wurden durch die Kombination von Röntgen‐Photoelektronenspektroskopie mit synchroner Beleuchtung und Dichtefunktionaltheorie untersucht.