Water electrolysis hydrogen production is based on electrolytic decomposition of water into hydrogen and oxygen. The process converts electrical energy into chemical energy.

• The core component is an electrolyzer equipped with an anode, a cathode, and an electrolyte, either aqueous electrolyte or solid electrolyte.
• After direct current is applied, water molecules gain electrons at the cathode and undergo reduction to generate hydrogen gas. Reaction at the cathode: 2H₂O + 2e⁻ → H₂↑ + 2OH⁻.
• At the anode, water molecules lose electrons and undergo oxidation to produce oxygen gas. Reaction at the anode: 2H₂O − 4e⁻ → O₂↑ + 4H⁺.
• The overall reaction is 2H₂O → 2H₂↑ + O₂↑. The electrolyte conducts ions and enables continuous electrochemical reactions.

A stable direct current power supply is required to provide electrical energy for electrolysis.

Electrolyte selection affects reaction efficiency, with common types including alkaline electrolyte, proton exchange membrane, and solid oxide electrolyte.

Operating temperature and pressure are adjusted according to electrolyte type to optimize electrolysis efficiency and gas purity.