Electrooxidation of methanol on NiMn alloy modified graphite electrode

Danaee, I ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.electacta.2009.11.039
  3. Abstract:
  4. Nickel and nickel-manganese alloy modified graphite electrodes (G/Ni and G/NiMn) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV), chronoamperometry (CA) and impedance spectroscopy (EIS) were employed. In CV studies, in the presence of methanol NiMn alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel hydroxide increase is followed by a decrease in the corresponding cathodic current in presence of methanol. The anodic peak currents show linear dependency upon the square root of scan rate. This behavior is the characteristic of a diffusion controlled process. Under the CA regime the reaction followed a Cottrellian behavior and the diffusion coefficient of methanol was found to be 4 × 10-6 cm2 s-1. A mechanism based on the electro-chemical generation of Ni3+ active sites and their subsequent consumptions by methanol have been discussed and the corresponding rate law under the control of charge transfer has been developed and kinetic parameters have been derived. The charge transfer resistance accessible both theoretically and through the EIS have been used as criteria for derivation of the rate constant
  5. Keywords:
  6. Oxidation of methanol ; Nickel ; Active site ; Alkaline solutions ; Anodic peaks ; Cathodic currents ; Charge transfer resistance ; Diffusion coefficients ; Diffusion-controlled process ; Electrocatalytic ; Electrocatalytic activity ; Galvanostatic deposition ; Impedance spectroscopy ; Linear dependency ; Methanol oxidation ; Modified electrode ; Modified electrodes ; Modified graphite electrodes ; Nickel hydroxides ; Manganese ; Peak currents ; Rate laws ; Redox process ; Scan rates ; Square roots ; Alloys ; Charge transfer ; Chronoamperometry ; Electrochemical corrosion ; Electrooxidation ; Graphite ; Ion exchange ; Manganese ; Manganese alloys ; Mass transfer ; Methanol ; Nickel ; Nickel alloys ; Process control ; Rate constants ; Graphite electrodes
  7. Source: Electrochimica Acta ; Volume 55, Issue 6 , 2010 , Pages 2093-2100 ; 00134686 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S0013468609014005