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Title: Photoemission Study of Glycine Adsorption on Cu/Au (111) Interfaces

Abstract

The adsorption of glycine on Au(1 1 1) pre-deposited with different amounts of Cu was investigated with both conventional X-ray photoelectron spectroscopy (XPS) and synchrotron-based photoemission. In the Cu submonolayer range, glycine physically adsorbs on the Cu/Au(1 1 1) surfaces in its zwitterionic form (NH{sub 3}{sup +}CH{sub 2}COO{sup -}) and completely desorbs at 350 K. The C 1s, O 1s and N 1s core level binding energies monotonically increase with Cu coverage. This indicates that, in the Cu submonolayer range, the admetal is alloyed with Au rather than forming overlayers on the Au(1 1 1) substrate, consistent with our recent experimental and theoretical results. Upon increasing the amount of deposited Cu over 1 ML, part of the glycine overlayer transforms from the zwitterionic form to the anionic form (NH{sub 2}CH{sub 2}COO{sup -}) and adsorbs chemically on the Cu/Au(1 1 1) surface with the N 1s binding energy shifted by -2.3 eV. When the amount of deposited Cu is at 3.0 or 6.0 ML, the intensity of the N 1s chemisorption peak increases with aging time at 300 K. It indicates that glycine adsorption induces Cu segregation from the subsurface region onto the top layer of the substrate. Judging from themore » initial N 1s peak intensities, it is concluded that 64% and 36% of the top layer are still occupied by Au atoms before glycine adsorption even when the amounts of deposited Cu are 3.0 and 6.0 ML, respectively. On the Au(1 1 1) surface pre-dosed with 6.0 ML of Cu, part of the chemisorbed glycine will desorb and part will decompose upon heating to 450-500 K. In addition, about 20% of the glycine exists in the neutral form when the glycine overlayer was dosed on Cu/Au(1 1 1) held at 100 K.« less

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
913971
Report Number(s):
BNL-78539-2007-JA
Journal ID: ISSN 0039-6028; SUSCAS; TRN: US0801439
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Surf. Sci.; Journal Volume: 600; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ADSORPTION; AGING; ATOMS; BINDING ENERGY; CHEMISORPTION; GLYCINE; HEATING; PHOTOEMISSION; SEGREGATION; X-RAY PHOTOELECTRON SPECTROSCOPY; NSLS; national synchrotron light source

Citation Formats

Zhao,X., and Rodriguez, J. Photoemission Study of Glycine Adsorption on Cu/Au (111) Interfaces. United States: N. p., 2006. Web. doi:10.1016/j.susc.2006.02.043.
Zhao,X., & Rodriguez, J. Photoemission Study of Glycine Adsorption on Cu/Au (111) Interfaces. United States. doi:10.1016/j.susc.2006.02.043.
Zhao,X., and Rodriguez, J. Sun . "Photoemission Study of Glycine Adsorption on Cu/Au (111) Interfaces". United States. doi:10.1016/j.susc.2006.02.043.
@article{osti_913971,
title = {Photoemission Study of Glycine Adsorption on Cu/Au (111) Interfaces},
author = {Zhao,X. and Rodriguez, J.},
abstractNote = {The adsorption of glycine on Au(1 1 1) pre-deposited with different amounts of Cu was investigated with both conventional X-ray photoelectron spectroscopy (XPS) and synchrotron-based photoemission. In the Cu submonolayer range, glycine physically adsorbs on the Cu/Au(1 1 1) surfaces in its zwitterionic form (NH{sub 3}{sup +}CH{sub 2}COO{sup -}) and completely desorbs at 350 K. The C 1s, O 1s and N 1s core level binding energies monotonically increase with Cu coverage. This indicates that, in the Cu submonolayer range, the admetal is alloyed with Au rather than forming overlayers on the Au(1 1 1) substrate, consistent with our recent experimental and theoretical results. Upon increasing the amount of deposited Cu over 1 ML, part of the glycine overlayer transforms from the zwitterionic form to the anionic form (NH{sub 2}CH{sub 2}COO{sup -}) and adsorbs chemically on the Cu/Au(1 1 1) surface with the N 1s binding energy shifted by -2.3 eV. When the amount of deposited Cu is at 3.0 or 6.0 ML, the intensity of the N 1s chemisorption peak increases with aging time at 300 K. It indicates that glycine adsorption induces Cu segregation from the subsurface region onto the top layer of the substrate. Judging from the initial N 1s peak intensities, it is concluded that 64% and 36% of the top layer are still occupied by Au atoms before glycine adsorption even when the amounts of deposited Cu are 3.0 and 6.0 ML, respectively. On the Au(1 1 1) surface pre-dosed with 6.0 ML of Cu, part of the chemisorbed glycine will desorb and part will decompose upon heating to 450-500 K. In addition, about 20% of the glycine exists in the neutral form when the glycine overlayer was dosed on Cu/Au(1 1 1) held at 100 K.},
doi = {10.1016/j.susc.2006.02.043},
journal = {Surf. Sci.},
number = 10,
volume = 600,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}