Electrocatalytic oxidation of methanol on poly(vinylferrocene) modified Pt electrode

Electrooxidation of methanol have been studied on the poly(vinylferrocene) (PVF) coated Pt substrate electrode and uncoated Pt substrate electrode in aqueous HClO4 solutions and the results have been compared. The effects of various parameters such as polymeric films thickness, potential scan rates, methanol concentration and media temperature on the electrooxidation of methanol have been investigated. The results have showed that the current values obtained for the electrooxidation of methanol have been up to 19 times higher than the current values obtained with bare Pt substrate under the same conditions. The Ea values for forward scan oxidation of methanol at PVF coated Pt substrate and Pt substrate electrode have been found to be 8.2 kJ mol−1 and 32.7 kJ mol−1, respectively. The Ea values for reverse scan oxidation at the PVF coated Pt substrate and Pt substrate electrode have also been calculated as 21.7 kJ mol−1 and 49.8 kJ mol−1, respectively. The Ea values for the PVF coated Pt substrate electrode are lower than Pt substrate electrode for methanol electrooxidation indicating that electrocatalytic activity of PVF. Electrooxidation of methanol in this system shows no significant effects of site poisoning by chemisorbed CO. Furthermore, our results suggest that the important role of OH chemisorbed onto polymer matrix in electrocatalysis of methanol on modified electrode. The catalytic efficiency of PVF towards oxidation of methanol has been determined and it has been found to be higher than 100% at all scan rates. The results suggest that the electrooxidation of methanol proceeds on the PVF modified Pt substrate electrode with good catalytic efficiency. Chronoamperometry experiments have been also confirmed electrocatalytic performance of the PVF coating.

► PVF coating on Pt surface possess a high electrocatalytical activity for methanol electrooxidation in acidic medium.
► High tolerance performance for adsorbed poisoning species on PVF coating.
► Lower Ea values for the PVF coated Pt electrode than Pt electrode.