 This means molecular hydrogen, H2, is combined with oxygen to form water.2H2 (4e−) + O2 --> 2H2O (4e−).The molecular hydrogen and oxygen's mutual affinity drives the fuel cell to separate the electrons from the hydrogen, to use them to power the electric motor, and to return them to the ionized water molecules that were formed when the electron-depleted hydrogen combined with the oxygen in the fuel cell.