We report here the first electrochemical pathway to prepare Au-containing nanocomplexes with the mean diameter of 2 nm in 0.1 N KCl aqueous solutions without addition of any stabilizer. Encouragingly, polypyrrole-(PPy-) coated gold nanocomposites with a core-shell structure and a diameter smaller than 8 nm can be prepared by the formation of self-assembled monolayers and further orderly autopolymerization of pyrrole monomers on these nanocomplexes. The prepared Au/PPy nanocomposites should exhibit extremely high conductivity, as indicated by the analyses of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and surface-enhanced Raman scattering (SERS). Meanwhile, elemental Au(0) nanoparticles of a mean diameter of 5 nm can be obtained by treating the Au/PPy-nanocomposites-containing solution with sonification.

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By combining techniques of underpotential deposition (UPD) and roughening metal substrates by a triangularwave oxidation-reduction cycle (ORC) which is generally used in surface-enhanced Raman scattering (SERS) studies, and extending applications of self-assembled monolayers (SAMs), copper is underpotentially deposited on electrochemically roughened Au(111) in this study for the first time. The formation of SAMs and further autopolymerization of pyrrole monomers are found on the UPD Cu-modified gold surfaces. The stability of SAMs is significantly improved due to the presence of UPD Cu. Furthermore, electropolymerized polypyrrole (PPy) on this UPD Cu-modified roughened Au demonstrates some distinguishing properties. These include higher conductivities, higher intensity, and better resolution on SERS and improved anti-aging ability in a 50% relative humility, 20% (v/v) O 2 atmosphere at 30 °C for 60 days.

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