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Adsorption and photolysis of trimethyl acetate on TiO2(B)(001) studied with synchrotron radiation core level photoelectron spectroscopy

Sandell, A.; Schaefer, A. LU ; Ragazzon, D.; Farstad, M. H. and Borg, A. (2017) In Surface Science 666. p.104-112
Abstract

We present a synchrotron radiation photoelectron spectroscopy study of the adsorption and photooxidation of trimethyl acetate (TMA) on TiO2(B)(001). The TiO2(B)(001) substrate was realized in the form of 2 nm thick film on Au(111). The TMA species adopt the bidentate bonding configuration, as expected for carboxylic acids on TiO2, but cannot coordinate to all surface Ti ions due to steric hindrance. The proposed arrangement of the TMA species thus allows for the formation of an overlayer with a (2 × 1) periodicity. The thermal stability is found to be comparable to that on rutile (110) although the results indicate differences in the threshold for the TMA + H→TMAA reaction. Photolysis using both... (More)

We present a synchrotron radiation photoelectron spectroscopy study of the adsorption and photooxidation of trimethyl acetate (TMA) on TiO2(B)(001). The TiO2(B)(001) substrate was realized in the form of 2 nm thick film on Au(111). The TMA species adopt the bidentate bonding configuration, as expected for carboxylic acids on TiO2, but cannot coordinate to all surface Ti ions due to steric hindrance. The proposed arrangement of the TMA species thus allows for the formation of an overlayer with a (2 × 1) periodicity. The thermal stability is found to be comparable to that on rutile (110) although the results indicate differences in the threshold for the TMA + H→TMAA reaction. Photolysis using both ultraviolet (UV) light and soft x-ray synchrotron radiation (SR) was studied and compared to the reaction on the reduced rutile (110) surface. A kinetic analysis suggests that the photoreaction rate for TMA on the TiO2(B) thin film is initially two times faster than that on the reduced rutile TiO2(110) surface. The higher activity of the TiO2(B) film is assigned to a reduced influence from surplus electrons associated with reduced Ti species, thereby decreasing the probability for hole-annihilation at high TMA coverage.

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organization
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type
Contribution to journal
publication status
published
subject
keywords
Adsorption, Carboxylic acids, Photocatalysis, Photoelectron spectroscopy, TiO(B), Titanium dioxide
in
Surface Science
volume
666
pages
9 pages
publisher
Elsevier
external identifiers
  • scopus:85029468038
  • wos:000413877900014
ISSN
0039-6028
DOI
10.1016/j.susc.2017.09.007
language
English
LU publication?
yes
id
4c043078-cb56-4f51-a482-a21cc482de0f
date added to LUP
2017-09-29 07:04:41
date last changed
2018-01-16 13:19:49
@article{4c043078-cb56-4f51-a482-a21cc482de0f,
  abstract     = {<p>We present a synchrotron radiation photoelectron spectroscopy study of the adsorption and photooxidation of trimethyl acetate (TMA) on TiO<sub>2</sub>(B)(001). The TiO<sub>2</sub>(B)(001) substrate was realized in the form of 2 nm thick film on Au(111). The TMA species adopt the bidentate bonding configuration, as expected for carboxylic acids on TiO<sub>2</sub>, but cannot coordinate to all surface Ti ions due to steric hindrance. The proposed arrangement of the TMA species thus allows for the formation of an overlayer with a (2 × 1) periodicity. The thermal stability is found to be comparable to that on rutile (110) although the results indicate differences in the threshold for the TMA + H→TMAA reaction. Photolysis using both ultraviolet (UV) light and soft x-ray synchrotron radiation (SR) was studied and compared to the reaction on the reduced rutile (110) surface. A kinetic analysis suggests that the photoreaction rate for TMA on the TiO<sub>2</sub>(B) thin film is initially two times faster than that on the reduced rutile TiO<sub>2</sub>(110) surface. The higher activity of the TiO<sub>2</sub>(B) film is assigned to a reduced influence from surplus electrons associated with reduced Ti species, thereby decreasing the probability for hole-annihilation at high TMA coverage.</p>},
  author       = {Sandell, A. and Schaefer, A. and Ragazzon, D. and Farstad, M. H. and Borg, A.},
  issn         = {0039-6028},
  keyword      = {Adsorption,Carboxylic acids,Photocatalysis,Photoelectron spectroscopy,TiO(B),Titanium dioxide},
  language     = {eng},
  month        = {12},
  pages        = {104--112},
  publisher    = {Elsevier},
  series       = {Surface Science},
  title        = {Adsorption and photolysis of trimethyl acetate on TiO<sub>2</sub>(B)(001) studied with synchrotron radiation core level photoelectron spectroscopy},
  url          = {http://dx.doi.org/10.1016/j.susc.2017.09.007},
  volume       = {666},
  year         = {2017},
}