Effect of Chloride Ions on the Adsorption of 3-Mercapto-1-propanesulfonic acid and Bis(3-sulfopropyl)-disulfide on a Au(111) Surface

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/50693

Title:	Effect of Chloride Ions on the Adsorption of 3-Mercapto-1-propanesulfonic acid and Bis(3-sulfopropyl)-disulfide on a Au(111) Surface
Authors:	Liu,YF;Lee,YL;Yang,YC;Jian,ZY;Dow,WP;Yau,SL
Contributors:	化學學系
Keywords:	SELF-ASSEMBLED MONOLAYERS;SCANNING-TUNNELING-MICROSCOPY;COPPER ELECTROPLATING BATH;LIGHT-EMITTING-DIODES;IN-SITU STM;4,5-DITHIAOCTANE-1,8-DISULFONIC ACID;ELECTROCHEMICAL DETECTION;MERCAPTOPROPIONIC ACID;GOLD ELECTRODE;CHEMISTRY
Date:	2010
Issue Date:	2012-03-27 18:08:04 (UTC+8)
Publisher:	國立中央大學
Abstract:	In situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV) were used to study the adsorption of 3-mercapto-1-propanesulfonic acid (MPS) and bis(3-sulfopropyl)-disulfide (SPS) on Au(111) electrode in a HClO(4) aqueous solution. Chloride ions were introduced into the electrolyte solution, and their effect on the adsorption behavior of MPS and SPS was investigated. The CV results show that SPS and MPS molecules preferentially adsorb on the Au(111) surface compared to chloride ions, and furthermore, chloride ion can induce the adsorption of thiol molecules on the Au(111) surface. In the absence of chloride, no adsorption phase of SPS (or MPS) adlayer can be imaged by STM at low potentials. Raising electrode potential leads to the appearance of disordered adsorption phase at ca. 0.4 V (vs RH E) and ordered adlattices at ca. 0.8 V. In the presence of chloride, ordered adsorption structures of SPS and MPS appear at a lower potential (0.2 V), implying the enhancement effect of chloride to the thiol adsorption. It is inferred that the presence of chloride ions triggers a more positively charged gold surface, enhancing the reaction rate of thiol adsorption. Furthermore, the presence of chloride also leads to a decrease in the thiol electrolyte interaction, due to the high solvation effect of chloride ions, which promotes the adsorption of SPS and MPS onto the Au surface. With further elevation of electrode potential, electrostatic interaction leads to coadsorption of chloride ions into the adlayer, as well as orientation changes of the ad-molecules. As a result, the ordered adlattice was disrupted and disappeared at ca. 0.5 V.
Relation:	LANGMUIR
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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