Electro-Catalytic Oxidation of Methanol on a Ni–Cu Alloy in Alkaline Medium
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The electro-catalytic oxidation of methanol on a Ni–Cu alloy (NCA) with atomic ratio of 60/40 having previously undergone 50 potential sweep cycles in the range 0–600 mV vs. (Ag/AgCl) in 1 m NaOH was studied by cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (EIS). The electro-oxidation was observed as large anodic peaks both in the anodic and early stages of the cathodic direction of potential sweep around 420 mV vs. (Ag/AgCl). The electro-catalytic surface was at least an order of magnitude superior to a pure nickel electrode for methanol oxidation. The diffusion coefficient and apparent rate constant of methanol oxidation were found to be 2.16 × 10−4 cm2 s−1 and 1979.01 cm3 mol−1 s−1, respectively. EIS studies were employed to unveil the charge transfer rate as well as the electrical characteristics of the catalytic surface. For the electrochemical oxidation of methanol at 5.0 m concentration, charge transfer resistance of nearly 111 Ω was obtained while the resistance of the electro-catalyst layer was ca. 329 Ω.
Keywordselectro-catalytic oxidation methanol nickel nickel–copper alloy
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Financial support of the research council of K. N. Toosi University of Technology is gratefully acknowledged. The authors also extend gratitude to Mr. M. Asgari for the skillful preparation of alloy samples.
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