Abstract: It is of technological value and scientific interest to the electro-synthesis of ferrocene, conversion of carbon dioxide (CO₂) and organic electro-synthesis in non-aqueous solutions by investigating the kinetics and mechanism toward electrochemical reductions of sodium bromide (NaBr) and methanol over iron electrodes. However, few reports in the related researches are available. In this article, the kinetics and mechanism toward electrochemical reductions of NaBr and methanol over iron electrodes were examined in detail by carrying out the polarization curve and electrochemical impedance spectroscopic measurements. The results showed that methanol was the reactant, while Na⁺ ions were functioned only as conducting species; the electrode potential was the only status variable, and its impact on the rate constants of the electro-reduction of methanol followed classic Arrhenius’s equation; the reduction was not limited by concentration diffusion, but mainly by the Ohmic polarization; the amount of H₂ gas production obeyed the Faraday’s law and the activation energy was evaluated to be ~26.2 kJ•mol^-1.

Key words: Methanol, Electro-reduction;  Sodium Bromide, Electrochemical impedance spectroscopy, Iron electrode