Considerable decrease in overvoltage of electro-catalytic oxidation of methanol by modification of carbon paste electrode with Cobalt(II)-clinoptilolite nanoparticles

Abstract

Clinoptilolite nanoparticles were ion exchanged in Co(II) solution and used for the modification of carbon paste electrode (Co(II)-NClin/CPE). The modified electrode showed good electrocatalytic behavior in oxidation of methanol at strong basic pHs (pH 13). The overvoltage of methanol electro-oxidation was decreased about 990 and 860 mV (vs Ag/AgCl) by the modified electrode with respect to raw CPE and Pt electrodes, respectively. The raw and Co(II)-exchanged clinoptilolites were characterized by XRD, TEM and BET methods. Apparent charge transfer rate constant and transfer coefficients for the modified electrode were respectively obtained as: ks = 0.011 s−1, ac = 0.43 and αa = 0.56 in the absence of methanol and αa = 0.69 in the presence of methanol. The catalytic rate constant (k) for the oxidation of methanol by the proposed electrocatalyst was also estimated about 254 M−1 s−1 by chronoamperometry.