Coadsorbate‐Induced Reversal of Solid–Liquid Interface Dynamics. Issue 21 (26th April 2018)

• Record Type: Journal Article
• Authors: Rahn, Björn; Wen, Rui; Deuchler, Lukas; Stremme, Johannes; Franke, Andreas; Pehlke, Eckhard; Magnussen, Olaf M.
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 21(2018)
• Page Start: 6065
• Page End: 6068
• Publication Date: 2018-04-26
• Subjects: density functional calculations -- electrochemistry -- scanning tunneling microscopy -- surface dynamics; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201712728
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: 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. Abstract : The influence of specifically adsorbed chloride and bromide ions on a Cu(100) surface on the diffusion of additionally adsorbed sulfur atoms has been studied experimentally and theoretically. Although the adsorbed halides show similar properties, sulfur diffusion on a bromide‐ or chloride‐covered Cu(100) surface shows an opposite dependence on the electrode potential.