Water electrolysis is the process of splitting water molecules. This process is carried out in the presence of an alkaline solution (electrolyte) and requires electricity as an input. The electrolyser cell splits water molecules into hydrogen and oxygen. The reaction is endothermic, which requires electricity as an energy input. A simple water electrolysis unit consists of an anode and a cathode, which are immersed in the electrolyte solution.

The electrodes are connected through an external DC power supply. When DC power is applied to the unit, electrons flow to the cathode from the negative terminal of the DC power source. At the cathode, the electrons combine with the hydrogen protons to produce H2. Then, H2 ions move toward the cathode, whereas hydroxide ions move towards the anode. H2 and oxygen gases develop at cathode and anode, respectively