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Title: Photocatalytic oxidation of the organic monolayers on TiO{sub 2} surface investigated by in-situ sum frequency generation spectroscopy

In-situ vibrational sum frequency generation (SFG) spectroscopy has been employed to investigate the photocatalytic oxidation of two types of well-ordered organic monolayers, namely, an arachidic acid (AA) monolayer prepared by the Langmuir-Blodgett method and an octadecyltrichlorosilane (OTS) monolayer prepared by the self-assembling method, on a TiO{sub 2} surface under ultraviolet (UV) irradiation. The extremely high sensitivity and unique selectivity of the SFG spectroscopy enabled us to directly probe the structural changes in these monolayers during the surface photocatalytic oxidation and further elucidate their reaction mechanisms at a molecular level. It was revealed that the ordering of the monolayers during the photocatalytic reaction is strongly dependent on their interaction with the substrate; the AA monolayer maintains its ordered conformation until the final oxidation stage, while the OTS monolayer shows a large increase in disordering during the initial oxidation stage, indicating a different photocatalytic reaction mechanism of the two monolayers on the TiO{sub 2} surface.
Authors:
; ; ; ;  [1]
  1. Catalysis Research Center, Hokkaido University, Sapporo 060-0811 (Japan)
Publication Date:
OSTI Identifier:
22415246
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL materials; Journal Volume: 3; Journal Issue: 10; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; EICOSANOIC ACID; IRRADIATION; OXIDATION; PHOTOCATALYSIS; REACTION KINETICS; SENSITIVITY; SILANES; SUBSTRATES; SURFACES; TITANIUM OXIDES; ULTRAVIOLET RADIATION