Product analysis of the ethanol oxidation reaction on palladium-based catalysts in an anion-exchange membrane fuel cell environment

摘要

We report a quantitative product analysis of the oxidation of ethanol in an anion-exchange membrane direct ethanol fuel cell (AEM DEFC) that consists of a Pd/C (or Pd_2Ni_3/C) anode, an AEM, and a Fe-Co cathode. The effects of the operating conditions including temperature, discharging current density, and fuel concentration, on the selectivity of each product of ethanol oxidation are investigated. It is found that incomplete ethanol oxidation to acetate prevails over complete oxidation to CO_2 in the range of testing conditions. Experimental results show that the change in the anode catalyst from Pd/C to Pd_2Ni_3/C leads to a significant increase in the cell performance, but does not help improve the CO_2 selectivity of ethanol oxidation. It is also shown that among the operating conditions tested, the operating temperature is the most significant parameter that affects the CO_2 selectivity: increasing the temperature from 60 to 100 ℃ enables the CO_2 current efficiency to increase from 6.0% to 30.6% with the Pd/C anode.