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Surface chemistry of glycine on Pt{111} in different aqueous environments

Shavorskiy, Andrey ; Eralp, Tugce ; Schulte, Karina LU ; Bluhm, Hendrik and Held, Georg (2013) In Surface Science 607. p.10-19
Abstract
Adsorption of glycine on Pt{111} under UHV conditions and in different aqueous environments was studied by XPS (UHV and ambient pressure) and NEXAFS. Under UHV conditions, glycine adsorbs in its neutral molecular state up to about 0.15 ML Further deposition leads to the formation of an additional zwitterionic species, which is in direct contact with the substrate surface, followed by the growth of multilayers, which also consist of zwitterions. The neutral surface species is most stable and decomposes at 360 K through a multi-step process which includes the formation of methylamine and carbon monoxide. When glycine and water are co-adsorbed in UHV at low temperatures (<170 K) inter-layer diffusion is inhibited and the surface... (More)
Adsorption of glycine on Pt{111} under UHV conditions and in different aqueous environments was studied by XPS (UHV and ambient pressure) and NEXAFS. Under UHV conditions, glycine adsorbs in its neutral molecular state up to about 0.15 ML Further deposition leads to the formation of an additional zwitterionic species, which is in direct contact with the substrate surface, followed by the growth of multilayers, which also consist of zwitterions. The neutral surface species is most stable and decomposes at 360 K through a multi-step process which includes the formation of methylamine and carbon monoxide. When glycine and water are co-adsorbed in UHV at low temperatures (<170 K) inter-layer diffusion is inhibited and the surface composition depends on the adsorption sequence. Water adsorbed on top of a glycine layer does not lead to significant changes in its chemical state. When glycine is adsorbed on top of a pre-adsorbed chemisorbed water layer or thick ice layer, however, it is found in its zwitterionic state, even at low coverage. No difference is seen in the chemical state of glycine when the layers are exposed to ambient water vapor pressure up to 0.2 Torr at temperatures above 300 K. Also the decomposition temperature stays the same, 360 K, irrespective of the water vapor pressure. Only the reaction path of the decomposition products is affected by ambient water vapor. (C) 2012 Elsevier B.V. All rights reserved. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ambient-pressure photoelectron spectroscopy, NEXAFS, Platinum, Glycine, Water, Heterogeneous catalysis
in
Surface Science
volume
607
pages
10 - 19
publisher
Elsevier
external identifiers
  • wos:000311134600003
  • scopus:84867898825
ISSN
0039-6028
DOI
10.1016/j.susc.2012.08.015
language
English
LU publication?
yes
id
b3633cc9-ae40-458a-b857-fa3de3748d18 (old id 3401217)
date added to LUP
2016-04-01 14:33:19
date last changed
2022-04-06 19:18:09
@article{b3633cc9-ae40-458a-b857-fa3de3748d18,
  abstract     = {{Adsorption of glycine on Pt{111} under UHV conditions and in different aqueous environments was studied by XPS (UHV and ambient pressure) and NEXAFS. Under UHV conditions, glycine adsorbs in its neutral molecular state up to about 0.15 ML Further deposition leads to the formation of an additional zwitterionic species, which is in direct contact with the substrate surface, followed by the growth of multilayers, which also consist of zwitterions. The neutral surface species is most stable and decomposes at 360 K through a multi-step process which includes the formation of methylamine and carbon monoxide. When glycine and water are co-adsorbed in UHV at low temperatures (&lt;170 K) inter-layer diffusion is inhibited and the surface composition depends on the adsorption sequence. Water adsorbed on top of a glycine layer does not lead to significant changes in its chemical state. When glycine is adsorbed on top of a pre-adsorbed chemisorbed water layer or thick ice layer, however, it is found in its zwitterionic state, even at low coverage. No difference is seen in the chemical state of glycine when the layers are exposed to ambient water vapor pressure up to 0.2 Torr at temperatures above 300 K. Also the decomposition temperature stays the same, 360 K, irrespective of the water vapor pressure. Only the reaction path of the decomposition products is affected by ambient water vapor. (C) 2012 Elsevier B.V. All rights reserved.}},
  author       = {{Shavorskiy, Andrey and Eralp, Tugce and Schulte, Karina and Bluhm, Hendrik and Held, Georg}},
  issn         = {{0039-6028}},
  keywords     = {{Ambient-pressure photoelectron spectroscopy; NEXAFS; Platinum; Glycine; Water; Heterogeneous catalysis}},
  language     = {{eng}},
  pages        = {{10--19}},
  publisher    = {{Elsevier}},
  series       = {{Surface Science}},
  title        = {{Surface chemistry of glycine on Pt{111} in different aqueous environments}},
  url          = {{http://dx.doi.org/10.1016/j.susc.2012.08.015}},
  doi          = {{10.1016/j.susc.2012.08.015}},
  volume       = {{607}},
  year         = {{2013}},
}