What are fuel cells? Describe the principle and overall reaction involved in the working of hydrogen–oxygen fuel cell or CH3OH – O2 fuel cell.
Fuel cells are the one where chemical energy is converted into electrical energy . The energy can be obtained indefinitely from a fuel cell as long as the outside supply of fuel is maintained. One of the examples is the hydrogen – oxygen fuel cell. The cell consists of three compartments separated by a porous electrode. Hydrogen gas is introduced into one compartment and oxygen gas is fed into another compartment. These gases then diffuse slowly through the electrodes and react with an electrolyte that is in the central compartment. The electrodes are made of porous carbon and the electrolyte is a resin containing concentrated aqueous sodium hydroxide solution. Hydrogen is oxidized at anode and oxygen is reduced at cathode. The overall cell reaction produces water. The reactions which occur are:
These types of cells are used in space – crafts. Fuel cells are efficient and pollution free.