Abstract
Methanol oxidation in fuel cells is an effective guarantor of renewable energy. So, this article investigates the electrochemical oxidation of methanol at various nickel-modified electrodes in NaOH solution using cyclic voltammetry and chronoamperometry techniques. Herein, a new electrochemical electrode was characterized by means of the scanning electron microscope (SEM), energy dispersive spectroscope (EDS), thermogravimetric analysis (TGA) and voltammetry method using a redox probe (ferricyanide). The catalytic activity of a new reduced p-nitroaniline/Ni(II) polymer transformed graphite electrode (poly-p-PD/Ni(II)/GE) for the oxidation of methanol is higher than that of the others. Quasi-reversible redox couple peaks were observed at + 0.25 and + 0.117 V and belong to the redox of Ni2+/Ni3+ cations. The surface coverage (Gamma) of electrochemical activity of the adsorbed redox cations at the surface of the poly-p-PD/Ni(II)/GE was estimated to be 4.1 x 10(-6) mmol/cm(2). The effect of scan rate (30-90 mV/s) for methanol in NaOH reveals the oxidation reaction of methanol under a diffusion-controlled process at the fabricated electrode. The values of electro-active surface area (A), transfer coefficient (alpha), number of electron transfers (n) and diffusion coefficient (D) have been calculated to be 0.562 cm(2), 0.183, 1 and 1.59 x 10(-4) cm(2)/s, respectively. The developed electrode used to be eventually displayed high stability while stored in the lab.