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Direct Observation of Oxygen Vacancy Self‐Healing on TiO 2 Photocatalysts for Solar Water Splitting
Author(s) -
Zhang Yajun,
Xu Zhongfei,
Li Guiyu,
Huang Xiaojuan,
Hao Weichang,
Bi Yingpu
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201907954
Subject(s) - x ray photoelectron spectroscopy , oxygen , materials science , chemical physics , vacancy defect , water splitting , metal , catalysis , nanotechnology , photochemistry , chemical engineering , chemistry , photocatalysis , crystallography , biochemistry , organic chemistry , engineering , metallurgy
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 TiO 2 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.