Structure of Tl adlayers on the Pt(111) electrode surface: Effects of solution pH and bisulfate coadsorption
- Brookhaven National Lab., Upton, NY (United States)
The structure of Tl adlayers deposited at underpotentials on Pt(111) has been investigated in four different electrolyte solutions (HClO{sub 4}, NaClO{sub 4}, NaOH, and H{sub 2}SO{sub 4}) with surface X-ray scattering (SXS) techniques. In all solutions investigated, Tl forms an incommensurate, aligned-hexagonal phase at the most negative potentials prior to its bulk deposition or hydrogen evolution. With decreasing potential the monolayer compresses and thus the Tl coverage increases. Under hydrogen evolution, the close-packed hexagonal Tl monolayer also exists and this reaction causes a slight lowering of the Tl coverage and a significant decrease of the in-plane ordering of the monolayer. In sulfuric acid solution, besides the close-packed hexagonal phase, a commensurate ({radical}3 x {radical}3)R30{degree} phase with a Tl coverage of 1/3 monolayer is formed in coadsorption with bisulfates over a 0.22 V wide potential range. 21 refs., 8 figs.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 380770
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 35 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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