Methanol Electrooxidation at Electrodes Made of Exfoliated Graphite/Nickel/Palladium Composite

Abstract

This paper try to answer the question, if the exfoliated graphite/nickel/palladium (EG/Ni/Pd) composite can be regarded as a potential anode material in direct methanol fuel cells (DMFCs). For this purpose, process of electrochemical oxidation of methanol on electrode made of EG/Ni/Pd was investigated. Electrochemical investigations were conducted in alkaline medium by cyclic voltammetry and potentiostatic techniques. Informations on catalytic activity of the examined composite were acquired from the comparison of current charges calculated for methanol oxidation peaks. The investigations revealed that electrochemical activity of EG/Ni/Pd composite enhances along the potential cycling. Current charges of methanol oxidation peaks increase with number of conducted cycles up to 26th cycle. The increment in electrochemical activity impacts on the decline in methanol concentration in the investigated electrolyte. The results of electrochemical investigations for EG/Ni/Pd composite were compared to that acquired for EG/Pd. The difference in total organic carbon (TOC) before and after the selected cycles of electrochemical process at EG/Ni/Pd electrode were the source of information on degree of methanol oxidation. Process comprised of 50 cycles of methanol electrooxidation resulted over 50% decrease in its concentration. The interpretation of electrochemical investigations were supported by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) analysis.