New pathway for the autopolymerization of pyrrole on the chlorine- and gold-containing complexes with nanostructures

Gold substrates were roughened by a triangular-wave oxidation-reduction cycle (ORC) for 25 scans in an aqueous solution containing 0.1 N KCl. The main Au(ClO₄)₄^- complexes with grain sizes smaller than 100 nm were formed on the roughened Au substrates, and the (220) face of Au partly changes into the (111) face with the lowest surface energy after ORC roughening. Then pyrrole (Py) monomers were encouragingly found to be autopolymerized on the roughened Au substrates due to the electrochemical activity of the complexes. The results indicate that the Au(ClO₄)₄^- complexes act as oxidants and the ClO₄^- or Cl^- ions act as dopants for the polymerization of Py and the further oxidation of polypyrrole (PPy), respectively. Meanwhile, formation mechanisms of the complexes and its electrochemical activity to the pyrrole polymerization and oxidation are proposed to illustrate these phenomena.