Improvement of the performance of a direct methanol fuel cell using a pulse technique

A pulse method is suggested for the improvement of the performance of a direct methanol fuel cell operated with PtRu anode and Pt cathode. The pulse method can be realized either in a potentiostatic or in a galvanostatic mode. In the galvanostatic regime of low current densities it allows for a temporary hoist of the cell voltage by up to 150 mV. It is suggested that by periodically applying a pulse to the fuel cell, the anode potential is shifted to positive values at which the otherwise high C Oads coverage on the PtRu anode is decreased by oxidation. After the pulse, the methanol oxidation rate is enhanced until the previous C Oads coverage is re-established and a new pulse is then applied. Differential electrochemical mass spectroscopy data reveal that an appreciable voltage gain can be obtained at a reduction of only ca. 10-15% of the C Oads saturation coverage.