Methanol adsorbates on the DMFC cathode and their effect on the cell performance

A drastic decline in the performance of a direct methanol fuel cell (DMFC) occurred after the cell had been operated at a higher temperature with higher methanol concentrations as compared with the polarization data collected under the original condition of a lower methanol concentration and room temperature. Both the linear sweep voltammetry (LSV) and cyclic voltarnmetry (CV) investigations suggest that the deterioration in the cell performance was due to the permeated methanol adsorbates on platinum sites of the cathode, which impede the oxygen reduction reactions (ORRs) by creating a large overpotential. The CV technique has further been utilized to get rid of the methanol adsorbates from the cathode electrochemically by sweeping from 0 to 1.0 V. After this procedure, both the open circuit voltage (OCV) and performance of the DMFC were found to be improved substantially. (c) 2005 Elsevier B.V. All rights reserved.