What are Electrolysers?

About Electrolysers

• It is an apparatus that produces hydrogen through a chemical process (electrolysis) capable of splitting water molecules into hydrogen and oxygen molecules by using electricity.

Working

• An electrolyser consists of a conductive electrode stack separated by a membrane to which a high voltage and current is applied.
• This causes an electric current in the water which causes it to break down into its components: hydrogen and oxygen.
• The oxygen generated in parallel is released into the atmosphere or can be stored for later use as a medical or industrial gas in some cases.
• The hydrogen is stored as a compressed gas or liquefied for use in industry or in hydrogen fuel cells, which can power transport vehicles such as trains, ships and even aircraft.

Types of Electrolysers

• Alkaline electrolysers: Alkaline electrolysis is a mature and commercially available technology used primarily by the fertiliser and chlorine industries.
• It presently accounts for almost two-thirds of the global electrolyser capacity.
• It uses thick membranes and nickel-based electrodes.
• Proton exchange membrane (PEM) electrolysers: It operates at high pressure, due to the use of thin perfluorosulfonic acid (PFSA) membranes.
• However, the PFSA acidic environment makes it necessary to use gold and titanium plated electrodes and metals such as platinum, iridium, and ruthenium as catalysts.
• They are the most popular because they produce high-purity hydrogen and are easy to cool. 
• Solid oxide electrolysis cell (SOEC) electrolysers : They utilise heat to make hydrogen from steam and are best placed where there is a heat source available (nuclear or industrial facilities).
• They operate at high temperatures (500 – 850degrees). 
• Anion exchange membrane (AEM) electrolysers: They operate at significantly lower temperatures of 50 – 60 degrees.
• They combine the less harsh conditions of alkaline electrolysers with the simplicity and high efficiency of PEM electrolysers.

Q1: What is hydrogen?

It is a clean alternative to methane, also known as natural gas. It's the most abundant chemical element, estimated to contribute 75% of the mass of the universe.

Source:Domestic manufacturing of electrolysers can be game changer for industrial emissions