Measurement of carbon dioxide yields for ethanol oxidation by operation of a direct ethanol fuel cell in crossover mode

Abstract

Faradaic yields of carbon dioxide from ethanol oxidation were measured with a non-dispersive CO2 detector for a direct ethanol fuel cell (DEFC) operating in crossover mode with aqueous ethanol delivered to the cathode and N2 passing through the anode compartment. Under these conditions, the rate of ethanol oxidation is limited by its rate of diffusion though the Nafion membrane (crossover). It is shown, by comparison with results obtained with methanol and by running the cell normally, that this experimental configuration provides more accurate results by minimizing the effects of CO2 crossover. The faradaic yield of CO2 was found to increase significantly with decreasing ethanol concentration, reaching 64% for oxidation of 0.1M ethanol at 80°C. However, the highest yield (>68%) was obtained by operating the cell normally.