Electrochemical system extracts pure hydrogen from ammonia at substantially lower temperatures

Ammonia, a liquid easily stored and transported, is being explored as a carrier for hydrogen, widely used in various applications. However, breaking ammonia into hydrogen and nitrogen traditionally requires high temperatures, and the hydrogen must undergo purification before use. MIT researchers have developed an electrochemical method to promote hydrogen release from ammonia while separating and concentrating it, reducing required temperatures and energy.

This approach generates highly concentrated, pure hydrogen streams, potentially paving the way for practical ways to store and distribute hydrogen. Electrochemistry promises to drive thermodynamically challenging dehydrogenation reactions, converting ammonia and liquid organic molecules into hydrogen gas at lower temperatures than conventional methods.

The key innovation is the coupling of a palladium-based separation membrane with a hydrogen-generating electrode through a molten hydroxide electrolyte. This setup selectively transports hydrogen while preventing other components from passing through, creating a "vacuum" that drives hydrogen towards the membrane and converting it into protons and electrons.

The membrane's selective transport of hydrogen produces a concentrated stream, eliminating the need for separate purification. This electrochemical process can continuously extract hydrogen, enhancing dehydrogenation reactions and operating at temperatures around 200-300 degrees Celsius, much lower than conventional ammonia cracking.

The method could be applied to other hydrogen carriers like methylcyclohexane, offering a viable pathway for transporting and using hydrogen.