05-07-2025
New plasma device turns air into ammonia, ends the need for fossil fuels
Researchers at the University of Sydney have developed a groundbreaking way to produce ammonia using electricity and artificial lightning. The innovation offers a cleaner, decentralized alternative to the Haber-Bosch process, which dominates global ammonia production but leaves a massive carbon footprint.
Ammonia, a key ingredient in fertilizers, supports nearly half of global food production. Traditionally, its production requires high heat, high pressure, and fossil fuels, making it one of the most emissions-intensive chemical processes in the world.
The Sydney team's approach uses plasma to excite nitrogen and oxygen in the air, then converts those molecules into ammonia gas through a membrane-based electrolyzer.
The study outlines how this two-step method avoids several inefficiencies of previous attempts. Most other labs had only managed to produce ammonia in liquid form, ammonium, which requires more processing to become usable gas. The new method bypasses that step.
'In this research we've successfully developed a method that allows air to be converted to ammonia in its gaseous form using electricity,' said Professor PJ Cullen, lead researcher from the University of Sydney's School of Chemical and Biomolecular Engineering. 'A huge step towards our goals.'
The development also opens the door to low-cost, scalable, and decentralized production of green ammonia, especially important for rural or off-grid locations.
'For the past decade, the global scientific community, including our lab, has wanted to uncover a more sustainable way to produce ammonia that doesn't rely on fossil fuels,' said Cullen.
Ammonia is gaining attention not just in agriculture but also in the energy sector. It contains three hydrogen atoms, making it an efficient way to store and transport hydrogen. Industry bodies are already exploring methods to extract hydrogen from ammonia by 'cracking' the molecules apart.
Ammonia's carbon-free profile also makes it a strong contender for future clean fuels. The shipping industry, which is responsible for about 3% of global emissions, is especially interested.
Cullen's team has worked on green ammonia technologies for six years. Their new setup centers on the membrane-based electrolyzer, a compact silver box where the final conversion occurs.
During the Haber-Bosch process, ammonia is produced by combining nitrogen and hydrogen gases under intense heat and pressure. Cullen's process uses plasma to energize air molecules and pass them through the electrolyzer to create ammonia directly.
'This new approach is a two-step process, namely combining plasma and electrolysis,' Cullen explained. 'We have already made the plasma component viable in terms of energy efficiency and scalability.'
However, he added, 'To create a more complete solution to a sustainable ammonia productive, we need to push the energy efficiency of the electrolyzer component.'
With ammonia production set to increase globally, this research could redefine how the world approaches one of its most important chemicals.
The study is published in the journal Angewandte Chemie International Edition.
