ELECTROLYSER TECHNOLOGIES · AWE
Follow the journey through a alkaline cell
Water reacts at the cathode. OH⁻ crosses to the anode. Electrons follow the external circuit.
Look for the glowing outline
Cell components and reaction reference
Build the cell: arrange components from anode side to cathode side
Anode: 2OH⁻ → ½O₂ + H₂O + 2e⁻
Cathode: 2H₂O + 2e⁻ → H₂ + 2OH⁻
Overall: H₂O → H₂ + ½O₂
Cathode: 2H₂O + 2e⁻ → H₂ + 2OH⁻
Overall: H₂O → H₂ + ½O₂
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Symbols and cell parts
- OH⁻
- Hydroxide ion: the mobile ionic carrier represented here; it moves from cathode to anode.
- Alkaline electrolyte
- An ion-conducting aqueous alkaline solution, commonly containing potassium hydroxide (KOH).
- Anolyte / catholyte
- The electrolyte on the anode side / cathode side.
- Separator / diaphragm
- A porous barrier that limits gas mixing while allowing ionic transport through its electrolyte-filled pores.
- Current collector
- An electronically conductive part connecting the electrode to the external circuit.
- Porous electrode
- An electrode with connected pores that help water and gases reach or leave the reaction sites.
- Anode (+)
- The positive electrode during electrolysis; oxidation releases electrons here.
- Cathode (−)
- The negative electrode during electrolysis; reduction consumes electrons here.
- DC power supply
- A direct-current source that supplies electrical energy and maintains the electrode potential difference.
- e⁻
- An electron. Electronic charge travels through conductive components and external wires.
- H₂O
- Water; H₂O(g) means water vapour (steam).
- H₂ / O₂
- Hydrogen gas / oxygen gas. Subscript ₂ means two atoms per molecule.
- OER / HER
- Oxygen evolution reaction / hydrogen evolution reaction.
- Oxidation / reduction
- Loss of electrons / gain of electrons.
- Reaction notation
- → means “forms”; + joins reactants or products. A coefficient such as 2 or ½ gives the relative number of molecules or moles.