Effect of Copper Alloying on Electro-Catalytic Activity of Nickel for Ethanol Oxidation in Alkaline Media

In this research, the electro-catalytic activity of nickel-copper (Ni-Cu) alloy towards oxidation of ethanol and its possible redox process were investigated in alkaline solution. For this purpose, cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques were employed. According to the cyclic voltammetry studies, Ni-Cu alloy compared to pure nickel can demonstrate a significantly higher response for ethanol oxidation. So, the enhancement of the anodic peak current corresponding to the oxidation of nickel hydroxide was accompanied with attenuated cathodic current in the presence of ethanol. The anodic peak currents have a linearly dependence on the square root of scan rate which is the characteristic of diffusion-controlled processes. Based on the chronoamperometry measurements, the reaction exhibited a Cottrellian behavior and the diffusion coefficient of ethanol was found to be 1.26 x 10(-5) cm(2) s(-1). The impedance spectroscopy declared electro-catalytic behavior of Ni-Cu electrode for oxidation of ethanol and showed that the charge transfer resistance decreases by increasing the ethanol concentration.