A comprehensive kinetic study on the electrocatalytic oxidation of propanols in aqueous solution

Abstract

The anodic peak current of a modified carbon paste electrode (CPE) with AgBr nanoparticles was increased in cyclic voltammetry (CV) by addition of 1-propanol or 2- propanol to supporting HCl electrolyte at pH 2.5. The kinetic aspects of the modified AgBr-CPE electrode response were studied in the absence and presence of the alcohols. The electrode response was irreversible based on a 135 mV difference for Epa-Epc and Ipa/Ipc = 0.88 for the AgIBr/AgIIBr redox process. The surface coverage concentration of the electrode, Γ, was about 13.1 μmol AgBr cm−2. The charge transfer coefficient, α, was 0.72 in HCl that was changed to 0.63 and 0.68 by addition of 1-propanol and 2-propanol in CV experiments, respectively, while its value was respectively changed from 0.72 to 0.61 and 0.51 in Tafel plots in LSV (linear sweep voltammetry). The rate constant value (k) was changed from 0.34 s−1 to 0.66 and 0.58 s−1 in CV experiments and from 0.31 s−1 to 0.58 and 0.51 s−1 in LSV experiments when the mentioned alcohols were added to the solution, respectively, confirms faster reaction rate in the presence of the alcohols.