Promoting Influence of Activated Carbon used in Carbon Paste Electrode on Platinum Nanoparticles Efficiency in Methanol Electrooxidation

Abstract

Direct methanol fuel cell (DMFC) have the advantages of low emissions of carbon dioxide, high power density and high energy density, so they have a great potential to replace fossil fuels. It is well known that Pt with high activity is an ideal catalyst for methanol oxidation in an acidic medium. However, it is an expensive material, and cost of the DMFC containing Pt is prohibitively high and it becomes poisoned by COads which is formed during the methanol oxidation. In this work, for the first time, the preparation of activated carbon(YBC) doped carbon paste electrode (YBCPE) and carbon paste electrode (CPE) were carried out for comparison. The electrochemical properties of YBCPE and CPE were investigated by electrochemical impedance spectroscopy. The electrodes of Pt/YBCPE and Pt/CPE were prepared by electrodeposition of platinum on YBCPE and CPE, respectively, at a constant potential (−0.1V vs. Ag|AgCl(sat)) in 0.5M H2SO4 containing 3mM H2PtCl6. The behavior of electrodeposition of platinum on YBCPE and CPE was studied through the application of theoretical models, and the morphology of Pt/YBCPE and Pt/CPE were characterized by SEM. The electrochemical activities of these catalysts towards methanol electrooxidation were examined by cyclic voltammetry. The influence of YBC mass percentage in YBCPE on both the electrode activity and long-term stability of electrodes in methanol electrooxidation was studied. It was shown that the addition of activated carbon improved the electrocatalytic activity of Pt catalysts on corresponding YBCPE toward methanol electrooxidation.