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Coadsorbate‐Induced Reversal of Solid–Liquid Interface Dynamics
Author(s) -
Rahn Björn,
Wen Rui,
Deuchler Lukas,
Stremme Johannes,
Franke Andreas,
Pehlke Eckhard,
Magnussen Olaf M.
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201712728
Subject(s) - isostructural , chemistry , diffusion , vacancy defect , sulfur , bromide , chemical physics , adsorption , chloride , aqueous solution , reactivity (psychology) , surface diffusion , inorganic chemistry , ion , crystallography , thermodynamics , organic chemistry , crystal structure , medicine , physics , alternative medicine , pathology
Coadsorbed anions are well‐known to influence surface reactivity and dynamics at solid–liquid interfaces. Here we demonstrate that the chemical nature of these spectator species can entirely determine the microscopic dynamic behavior. Quantitative in situ video‐STM data on the surface diffusion of adsorbed sulfur atoms on Cu(100) electrodes in aqueous solution covered by bromide and chloride spectators, respectively, reveal in both cases a strong exponential potential dependence, but with opposite sign. This reversal is highly surprising in view of the isostructural adsorbate arrangement in the two systems. Detailed DFT studies suggest an anion‐induced difference in the sulfur diffusion mechanism, specifically an exchange diffusion on the Br‐covered surface. Experimental evidence for the latter is provided by the observation of Cu vacancy formation in the Br system, which can be rationalized by a side reaction of the sulfur exchange diffusion.