A team of researchers led by RMIT University have released a study detailing a new method of making ammonia that utilises liquid metals as catalysts, reducing carbon emissions.
RMIT University’s low-carbon technique supports the decentralised, small-scale production of ammonia, where previously it was only possible to produce it at a large scale.
It involves using liquid metal droplets of copper and gallium to break apart the raw nitrogen and hydrogen, respectively, which combines to produce the low-carbon ammonia.
Since successfully proving the effectiveness of liquid metal catalysts, the RMIT research team has been working on upscaling and modifying their new technology for usage in a broader range of industries. One of their main objectives is to use this technology to facilitate the safe transportation of green energy globally.
Professor Torben Daeneke and Dr. Karma Zuraiqi, who led the research and study of liquid metal catalysts, further elaborated on its environmental and commercial benefits.
“Liquid metals allow us to move the chemical elements around in a more dynamic way that gets everything to the interface and enables more efficient reactions,” said Daeneke.
According to Zuraiqi, this method consumes “20 percent less heat and 98 percent less pressure”. As a result, it has a lower environmental cost than the traditional Haber-Bosch process which consumes 2 percent of global energy and accounts for 2 percent of global carbon emissions.
Additionally, RMIT’s method operates as effectively if not more than current techniques and at a fraction of the cost.
“It outperforms a lot of the state-of-the-art catalysts,” said Zuraiqi. Copper and gallium, the metals used by the research team, are readily available and cheaper than ruthenium, a precious metal used as a catalyst for current methods.
Behind the scenes of the research phase
The RMIT research team’s interest in exploring liquid metals as a possible catalyst for ammonia production goes back to 2020. While looking into the environmental and energy applications of liquid metal catalysts, they were inspired to appraise how they could be used for the century-old process of ammonia synthesis.
“We wanted to really start to probe how these catalysts would test in this application,” said Zuraiqi.
Adding on to Zuraiqi’s point, Daeneke pointed out the current lack of innovation in this area.
“We’re still using the same catalyst (force of pressure) that was developed 120 years ago,” he said. “There’s enormous carbon dioxide emissions that are caused by it.”
However, the team lacked the backing to conduct lab experiments until Daeneke met Serena (last name unknown), a professor who was able to provide them with the needed resources.
The experiment itself went smoothly, and the research team was able to confirm their hypothesis within their first attempt.
“In the end, the biggest challenge was to convince ourselves and the reviewers for our article that this was really happening because a lot of the findings were quite unexpected,” said Daeneke.
Future plans for their technology
With the success of their study behind them, their latest challenge is making it even more optimised for decentralised production.
“I think the main challenge now is that it’s something very new and we have to work with this industry to take it to the next step,” said Daeneke.
“We’ve shown it (our catalyst) works really well for 100, maybe 200 hours, but we need to show that it works for a year, two years, five years, something like that.”
To achieve this, the RMIT research team has been working on modifying their existing setup to operate at even lower pressures. At the same time, they’ve also expressed interest in speaking with potential partners who might want to scale it up for their industry.
“We could talk to big chemical producers, chemical manufacturing companies that already make ammonia on a vast scale and there might be some real advantages of using our catalyst over the existing ones,” said Daeneke. “But we’re also interested in working with more smaller scale operations because ammonia is more and more seen as a hydrogen carrier as well.”
They are especially focused on partnering with the hydrogen sector, recognising the growing need for advanced ammonia production technologies.
These technologies play a crucial role in ensuring the safe transport of hydrogen, facilitating its use as a clean and renewable energy solution.
Daeneke explained that Australia- which is located far away from regions such as the Middle East or Asia- could greatly benefit from the packaging of hydrogen into transportable chemical forms, which reduces the amount of hydrogen lost en route.
They’re optimistic that in the future, there will be a transition to a more sustainable industry that relies more on clean and sustainable energy.
“I don’t expect everybody to throw out the old catalysts tomorrow and take ours, but I think we will help us transition towards a more sustainable industry there over the next years,” said Daeneke.
Zuraiqi added on to his point and stated that a trend towards smaller-scale production would contribute greatly to an industry-wide move away from the Haber Bosch process.
“That’s when processes such as ours that operate at lower pressures could be really used in a more compact form. These start to become more viable options.”
In the big picture the research team has plans to further explore the potential of liquid metal catalysts, which are currently catching on in the field of chemistry. An ongoing big project involves using liquid metal catalysts to make hydrogen from fossil fuels.
“Liquid metal catalysts- they’re very new, they’re very exciting. A lot of chemists are working on this right now and more and more are joining in,” said Daeneke. “There’s a lot of work going on in Germany, also here in Australia.”
Many chemists are interested in the ways liquid metal catalysts can be applied to a range of different reactions, including hydrogen.
“There’s some very unique chemistry there that can be exploited.”
