electrolyser

An electrolyser, or electrolyzer, is an electrochemical device that uses electrical energy to drive a non-spontaneous chemical reaction, most commonly the decomposition of water into hydrogen and oxygen. In water electrolysis, the overall reaction is 2 H2O → 2 H2 + O2. Electrical energy is applied across two electrodes separated by an electrolyte.

There are several electrolyser technologies. Low-temperature types include alkaline systems that use a liquid electrolyte such as potassium hydroxide with nickel-based electrodes, and proton-exchange membrane (PEM) systems that use a solid polymer electrolyte and often noble-metal catalysts, operating around 60–80°C. High-temperature electrolyzers include solid oxide electrolyzers (SOECs) that operate at 700–1000°C and can use steam, which can improve efficiency by利用 process heat.

A typical electrolyser comprises an anode and a cathode separated by an electrolyte or a diaphragm, with gas diffusion layers, catalysts, water supply, and a gas-tight enclosure. The anode evolves oxygen and the cathode hydrogen, which are directed to appropriate gas-handling systems. Safety features address hydrogen flammability, venting, and leak detection.

Efficiency and cost depend on technology, scale, and operating conditions. Energy consumption is typically around 50–70 kWh per kilogram of hydrogen, depending on technology and operating conditions. High-temperature electrolysis can reduce electricity use by supplying process heat. Systems are increasingly deployed with renewable electricity to enable low-carbon hydrogen production.