Electrochemical impedance studies of methanol oxidation on GC/Ni and GC/NiCu electrode

Danaee, I ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijhydene.2008.10.067
  3. Publisher: 2009
  4. Abstract:
  5. The electro-oxidation of methanol on nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) in a 1 M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC/Ni corresponding to charge transfer resistance and adsorption of intermediates. Electro-oxidation of methanol on GC/NiCu shows negative resistance in impedance plots as signified by semi-circles terminating in the second quadrant. The impedance behavior shows different patterns at different applied anodic potential. The influence of the electrode potential on impedance pattern is studied and a mathematical model was put forward to quantitatively account for the impedance behavior of methanol oxidation. At potentials higher than 0.49 V vs. Ag/AgCl, a pseudoinductive behavior is observed but at higher than 0.58 V, impedance patterns terminate in the second quadrant. The conditions required for this behavior are delineated with the use of the impedance model. © 2008 International Association for Hydrogen Energy
  6. Keywords:
  7. Adsorption ; Catalysis ; Charge transfer ; Copper ; Electrocatalysis ; Electrochemical electrodes ; Electrochemistry ; Electrodes ; Electrolysis ; Glass membrane electrodes ; Ion exchange ; Nickel ; Nickel alloys ; Nyquist diagrams ; Oxidation ; Ag/AgCl ; Carbon electrodes ; Charge transfer resistances ; Electro-oxidation ; Electrochemical impedance (EIS) ; Electrode potentials ; Equivalent circuit ; Impedance ; Impedance modelling ; Impedance spectroscopy (IS) ; Methanol oxidation ; NaOH solutions ; Methanol
  8. Source: International Journal of Hydrogen Energy ; Volume 34, Issue 2 , 2009 , Pages 859-869 ; 03603199 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0360319908014341