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Cleaner, greener ammonia


A method of producing ammonia could yield a greener route to nitrogen-based fertilizers.

Ammonia is currently synthesized by combining nitrogen and hydrogen under high pressures and temperatures in a reaction called the Haber–Bosch process. Making the hydrogen consumes around 5% of the world's natural-gas production, and releases large amounts of carbon dioxide.

Stuart Licht at George Washington University in Washington DC and his colleagues applied a voltage to steam and air (the source of nitrogen) bubbling through molten hydroxide containing catalytic nanoparticles of iron oxide. This produced ammonia from nitrogen and water directly by electrolysis. The nanoparticles clump together over time, slowing the reaction, and moderate temperatures and pressures are still needed. However, if the process can be scaled up, it could be less energy-intensive than the current industrial method.

Science 345, 637–640 (2014)

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Cleaner, greener ammonia. Nature 512, 116 (2014).

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