Chemical Research in Chinese Universities ›› 2012, Vol. 28 ›› Issue (1): 19-25.

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Electrochemical Impedance of Ethanol Oxidation in Alkaline Media

DANAEE Iman1, JAFARIAN Majid2*, GOBAL Fereydoon3, SHARAFI Mahboobeh2, MAHJANI Mohammad-ghasem2   

  1. 1. Abadan Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan 63165-619, Iran;
    2. Department of Chemistry, K. N. Toosi University of Technology, Tehran 15875-4416, Iran;
    3. Department of Chemistry, Sharif University of Technology, Tehran 11365-9516, Iran
  • Received:2011-04-21 Revised:2011-08-30 Online:2012-01-25 Published:2011-12-27
  • Contact: Iman Danaee E-mail:mjafarian@kntu.ac.ir

Abstract: Nickel modified NiOOH electrodes were used for the electrocatalytic oxidation of ethanol in alkaline solutions. The electro-oxidation of ethanol in a 1 mol/L NaOH solution at different concentrations of ethanol was studied by ac impedance spectroscopy. Electrooxidation of ethanol on Ni shows negative resistance on impedance plots. The impedance shows different patterns at different applied anodic potential. The influence of the electrode potential on impedance was studied and a quantitative explanation for the impedance of ethanol oxidation was given by means of a proposed mathematical model. At potentials higher than 0.52 V(vs. Ag/AgCl), a pseudoinductive behavior was observed, but at those higher than 0.57 V, impedance patterns were reversed to the second and third quadrants. The conditions required for the reversing of impedance pattern were delineated with the impedance model.

Key words: Impedance, Equivalent circuit, Ethanol, Electrocatalytic, Nickel