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Adsorption of Iodide and Bromide on Au(111) Electrodes from Aprotic Electrolytes: Role of the Solvent
Author(s) -
Shatla Ahmed S.,
Bawol Pawel P.,
Baltruschat Helmut
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202001296
Subject(s) - chemistry , propylene carbonate , adsorption , iodide , inorganic chemistry , bromide , solvent , solvation , cyclic voltammetry , x ray photoelectron spectroscopy , electrolyte , electrochemistry , electrode , organic chemistry , physics , nuclear magnetic resonance
Abstract The adsorption of iodide and bromide ions on Au(111) single‐crystal electrodes in three organic solvents [propylene carbonate (PC), diglyme (DG), and dimethyl sulfoxide (DMSO)] was studied by differential capacity measurements, cyclic voltammetry (CV), X‐ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The anion adsorption charge in DMSO is approximately half as large as in propylene carbonate and that in water. Quantification of the adsorbed iodide amount from XPS spectra confirms the coverage estimated from the adsorption charge in CVs. As expected, the rate of anion adsorption on Au(111) is higher for I − than for Br − due to better solvation of the latter. The extent of anion adsorption on Au(111) electrode decreases and the corresponding adsorption rate decreases in the solvent order H 2 O>PC>DG>DMSO. Since the donor number (DN) of the solvent increases in the same order (PC