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Analysis:
On the cathode side, the catalytic reaction of hydrogen with oxygen from the ambient air forms
water as a result.
Direct-ethanol fuel cells or DEFCs are a subcategory of Proton Exchange Membrane (PEM) fuel
cells where, the ethanol fuel is not first reformed into pure hydrogen, but fed directly to the fuel
cell's membrane.
The mechanism is as follows:
Anode:
(1) C2H5OH → CH3CHO + 2H
(2) C2H5OH + H2O → CH3COOH + 4H
(3) C2H5OH + 3H2O → 2CO2 + 12 H
Cathode:
+
-
4H
+ 4e
+O2→2H2O
During the reaction, some of the ethanol is oxidated completely and turns into CO2 (as in the
reaction #3, while some of the ethanol is oxidated incompletely and turned into acetaldehyde and
acetic acid (as in the reactions #1 and #2 ).
Conclusion:
The Direct Ethanol Fuel Cell produces electricity while ethanol reacts at the anode side of the fuel
cell. Hydrogen protons permeate from the ethanol solution through the DEFC's membrane,
liberating electrons that are captured in an external circuit.
+
-
+ 2e
+
-
+ 4e
+
-
+ 12 e
58
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