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

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 over voltage 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: k(s) = 0.011 s(-1), = 0.43 a(c) = 0.43 and alpha(a) = 0.56 in the absence of methanol and alpha(a) = 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. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.