In-situ X-ray diffraction and STM studies of bromide adsorption on Au(111) electrodes

Journal Article · Thu Mar 28 04:00:00 EST 1996 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp953281j· OSTI ID:226685

Magnussen, O M; Ocko, B M; Wang, J X; Adzic, R R ^[1]

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1. Brookhaven National Lab., Upton, NY (United States)

The structure of bromide adlayers at the Au(111)-aqueous solution interface has been studied by in-situ surface X-ray scattering (SXS) and scanning tunneling microscopy (STM). Both techniques show the existence of a hexagonal close-packed adlayer phase above a critical potential and are in good quantitative agreement on the adlayer structural parameters. The bromide-bromide spacing changes continuously between 4.24 A at the critical potential and 4.03 A at a potential 300 mV more positive. The adlayer is rotated relative to the substrate by an angle dependent on potential and bromide concentration. The potential- dependent adlayer density corresponding to these structural results agrees well with Br surface excess densities from published electrochemical measurements. At very positive potentials a bromide-induced step-flow etching of the Au substrate is observed. The results are used to compare the different techniques and to discuss the adlayer structure, the phase behavior, and the halide-gold chemical interaction. 49 refs., 8 figs.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 226685
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 13 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ADSORPTION
AQUEOUS SOLUTIONS
BROMIDES
ELECTRIC POTENTIAL
ELECTRODES
FILMS
GOLD
INTERFACES
MICROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
X-RAY DIFFRACTION