Comparison of the Voltammetric Behavior of Adsorbed or Dissolved Unsaturated Alcohols at Vacuum-Annealed and Electrochemically Cycled Pt(111) and Pt(Polycrystalline) Electrodes

摘要

Recent investigations of unsaturated alcohols have focused upon the characterization of molecular layers adsorbed from both aqueous solutions and the neat liquids at Pt(111). The mode of surface attachment was deduced by surface vibrational studies (electron energy-loss spectroscopy, EELS), molecular packing density and elemental composition data (Auger spectroscopy), and electrochemical reactivity (cyclic voltammetry and chronocoulometry). The subject unsaturated alcohols were found to form chemisorbed layers by attachment through the unsaturated moiety. Comparison of the reaction energetics, kinetics, and stoichiometry of the adsorbed layers with the behavior of the same compounds in aqueous solution provides an immediate indication of the extent to which the electrochemical reactivity of dissolved unsaturated alcohols resembles the reactivity of the adsorbed intermediates. The present studies compare the voltammetric behavior of dissolved and adsorbed unsaturated alcohols (alkenes, alkynes, and aromatics) on electrochemically cycled and UHV-annealed PT(111) surfaces. Also included are voltammetric scans of the adsorbed alcohols at Pt(polycrystalline) (Pt(poly)). Adsorption of the subject unsaturated aliphatic alcohols in this study from dilute aqueous solutions indicates the adsorption of a substantial amount of CO. Keywords: Electrochemistry; Reprints. (KT)