Coadsorption of sulfate/bisulfate anions with Hg cations during Hg underpotential deposition on Au(111): An in situ x-ray diffraction study

Journal Article · Thu Jan 09 04:00:00 EST 1997 · Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical

DOI:https://doi.org/10.1021/jp961857e· OSTI ID:501910

Li, J; Abruna, H D ^[1]

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1. Cornell Univ., Ithaca, NY (United States)

The first stage of mercury underpotential deposition on Au(111) electrodes in 0.10 M H{sub 2}SO{sub 4} containing 1.0 mM Hg{sup 2+} has been studied by synchrotron X-ray scattering techniques including grazing incidence X-ray diffraction and specular crystal truncation rod measurements. An ordered coadsorbed structure of sulfate/bisulfate anions and Hg cations was found at potentials between the first and second Hg UPD peaks (+0.80 V > E > +0.88 V vs Ag/AgCl(3 M KCl)). The coadsorption structure was found to consist of a compressed Hg honeycomb lattice with the honeycomb centers occupied by sulfate or bisulfate anions. The compression of the lattice is likely due to the formation of mercurous (Hg{sub 2}{sup 2+}) ions which have a much shorter Hg-Hg distance than that in frozen bulk Hg crystals. The net charge transferred under the first Hg UPD peak suggests that the chemical state of the species in the coadsorbed structure is likely Hg{sub 2}SO{sub 4}. Our results indicate that both the chemical state of the mercury cations and the nature of the anions are important in the resulting electrodeposited structures. 38 refs., 8 figs., 1 tab.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 501910
• Journal Information: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 2 Vol. 101; ISSN 1089-5647; ISSN JPCBFK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ADSORPTION
ANIONS
CATIONS
ELECTRODEPOSITION
MERCURY IONS
SULFATES
VOLTAMETRY
X-RAY DIFFRACTION