Open AccessChemisorbed and Physisorbed Water at the TiO2/Water Interface
Author(s) -
Saman Hosseinpour,
Fujie Tang,
Fenglong Wang,
Ruth A. Livingstone,
Simon J. Schlegel,
Tatsuhiko Ohto,
Mischa Bonn,
Yuki Nagata,
Ellen H. G. Backus
Publication year - 2017
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.7b00564
Subject(s) - superhydrophilicity , anatase , dissociation (chemistry) , hydrogen , molecule , hydrogen bond , chemical physics , chemistry , photochemistry , adsorption , chemisorption , oxygen , molecular dynamics , materials science , photocatalysis , contact angle , computational chemistry , catalysis , organic chemistry , composite material
The interfacial structure of water in contact with TiO 2 is the key to understand the mechanism of photocatalytic water dissociation as well as photoinduced superhydrophilicity. We investigate the interfacial molecular structure of water at the surface of anatase TiO 2 , using phase-sensitive sum frequency generation spectroscopy together with spectra simulation using ab initio molecular dynamic trajectories. We identify two oppositely oriented, weakly and strongly hydrogen-bonded subensembles of O-H groups at the superhydrophilic UV irradiated TiO 2 surface. The water molecules with weakly hydrogen-bonded O-H groups are chemisorbed, i.e. form hydroxyl groups, at the TiO 2 surface with their hydrogen atoms pointing toward bulk water. The strongly hydrogen-bonded O-H groups interact with the oxygen atom of the chemisorbed water. Their hydrogen atoms point toward the TiO 2 . This strong interaction between physisorbed and chemisorbed water molecules causes superhydrophilicity.