Electrolysis of water by using a source of renewable energy is an important technology for carbon-free hydrogen production. This reaction takes place in a unit called an electrolyzer. Based on the types of electrolytes and operating conditions, electrolyzers can be classified into three main categories:
1 ) alkaline water electrolyzer (AWE)
Alkaline electrolyzers operate via transport of hydroxide ions (OH-) through the electrolyte from the cathode to the anode with hydrogen being generated on the cathode side. Electrolyzers using a liquid alkaline solution of sodium or potassium hydroxide as the electrolyte have been commercially available for many years. Newer approaches using solid alkaline exchange membranes (AEM) as the electrolyte are showing promise on the lab scale.
Anode Reaction: 4OH– → O2 + 2H2O + 4e–
Cathode Reaction: 2H2O + 2e– → H2 + 2OH–
2 ) high temperature solid oxide electrolyzer (SOE)
3 ) proton exchange membrane(PEM) electrolyzer
In a polymer electrolyte membrane (PEM) electrolyzer, the electrolyte is a solid specialty plastic material.Water reacts at the anode to form oxygen and positively charged hydrogen ions (protons).The electrons flow through an external circuit and the hydrogen ions selectively move across the PEM to the cathode.At the cathode, hydrogen ions combine with electrons from the external circuit to form hydrogen gas.
Anode Reaction: 2H2O → O2 + 4H+ + 4e–
Cathode Reaction: 4H+ + 4e– → 2H2
Platinum-based materials are presently recognized as the state-of-the-art electro-catalysts for the cathode side in PEM electrolyzers, which exhibit decent electrochemical activity for the hydrogen evolution reaction (HER) in acidic electrolytes.
In view of cost reduction and high efficiency, our platinum coated titanium mesh electrode is a promising option for long-lasting performance.
