A fuel cell can be defined as an electrochemical cell that generates electrical energy from fuel via an electrochemical reaction. These cells require a continuous input of fuel and an oxidizing agent in order to sustain the reactions that generate the electricity. Therefore, these cells can constantly generate electricity until the supply of fuel and oxygen is cut off.
Working of Fuel Cell
The fuel cell worked by transferring hydrogen and oxygen via carbon electrodes into a concentrated sodium hydroxide solution. The following is an equation for the cell reaction:
Cathode Reaction: O2 + 2H2O + 4e– → 4OH–
Anode Reaction: 2H2 + 4OH– → 4H2O + 4e–
Net Cell Reaction: 2H2 + O2 → 2H2O
This electrochemical reaction, however, has a slow reaction rate. A catalyst, such as platinum or palladium, is used to solve this issue. To increase the effective surface area, the catalyst is finely divided before being incorporated into the electrodes.