3-Mercapto-l-propanesulfonic acid and bis(3-sulfopropyl) disulfide adsorbed on Au(111): In situ scanning tunneling microscopy and electrochemical studies

Zheng Yan Jian, Teng Yuan Chang, Yaw Chia Yang, Wei Ping Dow, Shueh Lin Yau, Yuh Lang Lee

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

3-Mercapto-l-propanesulfonic acid (MPS) and bis(3-sulfopropyl) disulfide (SPS) adsorbed on a Au(111) electrode were studied by using in situ scanning tunneling microscopy (SIM). Although the adsorptions of MPS and SPS are known to be oxidative and reductive, respectively, on an Au(111) electrode, these two admolecules behave similarly in terms of phase evolution, surface coverage, potential for stripping, and characteristics of cyclic voltammetry. However, different adsorption mechanisms of these molecules result in different structures. Raising electrode potential causes more MPS and SPS molecules to adsorb, yielding ordered adlattices between 0.67 and 0.8 V (vs reversible hydrogen electrode). The ordered adlattices of MPS and SPS appear as striped and netlike structures with molecules adsorbed parallel to the Au(111) surface. Switching potential to 0.9 V or more positive still does not result in upright molecular orientation, possibly inhibited by electrostatic interaction between the end group of -SO3- and the Au(111) electrode. Lowering the potential to 0.4 V disrupted the ordered adlayer. Stripping voltammetric experiments show that MPS and SPS admolecules are desorbed from Au(111) at the same potential, suggesting that these molecules are both adsorbed via their sulfur headgroups. The S-S bond in SPS is likely broken upon its adsorption on Au(111).

Original languageEnglish
Pages (from-to)179-184
Number of pages6
JournalLangmuir
Volume25
Issue number1
DOIs
Publication statusPublished - 2009 Jan 6

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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