
205Electrochemical Kinetics
It should be noted that this model has limitations as it does not account for
(i) the inert gases or impurities present with reactants such as nitrogen in air
or the presence of carbon monoxide or carbon dioxide when hydrogen is sup-
plied from a fuel reformer, and (ii) the production and removal of reaction
products, such as water.
Example 5.6
For fuel cell, the limiting current density for anode is 20 A/cm
2
and that
for the cathode is 2 A/cm
2
. Assuming single electron transfer reaction
steps both at anode and cathode, determine the mass transfer overpoten-
tial for anode and cathode if the fuel cell is operating at 80°C ...