The hydrogen fuel cell is not new; the first one was invented in 1838. Interestingly, it was never used as a commercial source of energy until the NASA Apollo Project went to the Moon. The fuel cell is a simple device often compared to a battery. It consists of an anode and a cathode separated by a proton (H+) exchange membrane. The anode contains a catalyst that causes hydrogen gas to be oxidized, producing hydrogen ions (H+) and electrons (e-). After the reaction, the hydrogen ions are drawn through the proton exchange membrane which only allows positive ions to pass through to the cathode. The electron are simultaneously drawn through an external circuit (wire) to the cathode, producing direct current electricity. At the cathode, the hydrogen ions, the electrons and oxygen gas are combined to form water:
O2 + 4H+ + 4e- → 4H2O
The net reaction is:
2H2 + O2 → 2H2O
As a result, the fuel cell produces a direct electrical current with the only byproduct being water. While the hydrogen fuel cell produces an electric potential of only 0.7 volts, they can be stacked like the cells in car battery to create sufficient voltage to meet the need of any application. Fuel cells also generate heat which, if captured for use such as heating a house, increases the efficiency to about 85%.
hydrogen fuel cell