UNSW researchers create device showing potential for onsite ammonia production on farms

UNSW Sydney engineering researchers have created a system based on a solar PV panel and a photocatalyst, able to create ammonia from wastewater and likened to a leaf.

According to a statement from the university on Monday, a team led by UNSW Scientia Professor Rose Amal and Professor Xiaojing Hao used a “nano-structured thin layer of copper and cobalt hydroxide” catalyst on the silicon panel to assist a chemical reaction for producing ammonium nitrate from water.

The “artificial leaf” can work in ambient conditions and using only sunlight as power.

Their results were published in a paper in the Journal of Energy and Environmental Science (linked.)

Ammonia is an important chemical used in fertilisers, and production traditionally creates a large amount of greenhouse gas due to a reliance on fossil fuels.

Other efforts to create greener fertiliser materials include Jupiter Ionics’ electrolysis-based process for green ammonia, which came out of Monash University research. The company announced a $9 million capital raise in March.

The UNSW team has built a 40 centimetre square system on the roof of the university’s Tyree Energy Technologies building at Kensington, which has so far been able to produce enough ammonium ions for 1.49 square metres of cropland.

The results have been good enough to make the researchers to want to scale up.

“You do not need a high concentration of ammonia in fertiliser so we believe the amounts of ammonia we are producing using our system make it a viable application in the real world, although we definitely still have some ways to further improve it,” said lead author Chen Han.

Amal added: “We think this new technology could be implemented on a relatively small scale in agricultural locations to produce ammonium onsite, which would decentralise the production process and further reduce CO2 emissions that are associated with the transportation process.

She noted that it’s important to recognise that the wastewater used wasn’t directly from municipal waste or runoff, and requires organic matters and particulates to be filtered out.

“But we are hopeful that once we have generated ammonium from the nitrate wastewater, the treated water can then be put into irrigation.”

Picture: The “artificial leaf” system (credit Chen Han/UNSW)

Further reading

Sydney researchers develop 100 per cent renewable hydrogen

Amp Energy plans green hydrogen and ammonia production

Green ammonia company Jupiter Ionics raises $9 million