Evaluation of Ethanol, 1‐Propanol, and 2‐Propanol in a Direct Oxidation Polymer‐Electrolyte Fuel Cell: A Real‐Time Mass Spectrometry Study

Ethanol, 1‐propanol, and 2‐propanol have been evaluated as alternative fuels for direct methanol/oxygen fuel cells. The relative product distributions for the electro‐oxidation of these alcohols under fuel‐cell conditions were determined using on‐line mass spectrometry. For water/ethanol mole ratios between 5 and 2, ethanal is the main product, while is a minor product. However, an increase of the water/ethanol mole ratio increased the relative product distribution of slightly. Propanal was the main product of the electro‐oxidation of 1‐propanol with a similar percentage of being formed as for ethanol. In contrast, the electro‐oxidation of 2‐propanol yielded practically only acetone. Between 150 and 190°C, the product distributions for the electro‐oxidation of ethanol, 1‐propanol, and 2‐propanol do not depend significantly on the temperature. No differences in the product selectivities of Pt‐Ru and Pt‐black were found. Ethanol is a promising alternative fuel for direct methanol fuel cells (DMFCs) with an electrochemical activity comparable to that of methanol. Conversely, 1‐propanol and 2‐propanol are not suitable as fuels for DMFCs due to their low electrochemical activity.