In situ STM and ex situ XPS examination of the adsorption and polymerization of metanilic acid and aniline on Au(1 1 1) electrode

Sihzih Chen, Shuehlin Yau, Liangjen Fan, Yawwen Yang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Oxidation of aniline and its derivatives can yield cationic radicals, which induce chain reactions to produce polymeric materials with notable conductivity. When these events occur on ordered electrode surface, admolecules can be adsorbed in some specific manner that guides reactions to proceed in some specific directions to yield products with well-defined conformations. This study employed cyclic voltammetry, X-ray photoemission spectroscopy (XPS), and in situ scanning tunneling microscopy (STM) to study the adsorption and polymerization of metanilic acid (MA) in 0.5 M H2SO4. MA molecules were adsorbed in highly ordered adlattices characterized as Au(1 1 1) - (19 × 31) and (27 × 31) at 0.5 and 0.8 V (vs. reversible hydrogen electrode). These adlattices were displaced by bisulfate anions at E > 1.0 V. MA molecules still could be oxidized to yield polymer molecules, which lacked a well-defined structure. By contrast, MA and aniline molecules could be coadsorbed in a highly ordered Au(1 1 1) - (4 × 23) structure at 0.8 V in 0.5 M H2SO4 + 30 mM aniline + 3 mM MA, which led to anisotropic oxidative polymerization.

Original languageEnglish
Pages (from-to)150-157
Number of pages8
JournalJournal of Electroanalytical Chemistry
Volume716
DOIs
StatePublished - 1 Mar 2014

Keywords

  • Aniline
  • Au(1 1 1) single crystal electrode
  • Electropolymerization
  • In situ scanning tunneling microscopy
  • Metanilic acid
  • Molecular adlayer

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