Hydrogen, Renewables

RMIT University researchers make breakthrough in green hydrogen production

A team of researchers from RMIT University has taken a giant leap in the quest to make commercially viable green hydrogen by extracting it from seawater without desalination, writes Gareth Pye.

Researchers from RMIT University in Melbourne have made a breakthrough in the commercial viability of green hydrogen production by developing a method of extracting it directly from seawater.

The innovative discovery from the Materials for Clean Energy and Environment (MC2E) research group at RMIT splits seawater directly into hydrogen and oxygen, skipping the need for the expensive desalination process, which is expensive, consumes energy and produces carbon emissions.

Green hydrogen derived from splitting water currently comprises just one per cent of global hydrogen production due to the cost, meaning a majority of the world’s hydrogen production relies on fossil fuels and is responsible for emitting 830 million tons of carbon dioxide per year, according to the International Energy Agency.

However, this latest breakthrough utilising seawater can help propel green hydrogen as a future clean fuel, particularly in high-carbon producing industries such as aviation, shipping and manufacturing.

“We know hydrogen has immense potential as a clean energy source, particularly for the many industries that can’t easily switch over to be powered by renewables,” says Vice-Chancellor’s Senior Research Fellow at RMIT, Dr Nasir Mahmood, who is lead researcher on the project.

“But to be truly sustainable, the hydrogen we use must be 100 per cent carbon-free across the entire production lifecycle and must not cut into the world’s precious freshwater reserves.

“Our method to produce hydrogen straight from seawater is simple, scaleable and far more cost-effective than any green hydrogen approach currently in the market.

“With further development, we hope this could advance the establishment of a thriving green hydrogen industry in Australia.”

From left: Suraj Loomba, Dr Nasir Mahmood and Dr Muhammad Waqas Khan from the Materials for Clean Energy and Environment research team at RMIT University. Photo: RMIT University.

To make green hydrogen, an electrolyser is used to send an electric current through water to split it into its component elements of hydrogen and oxygen.

These electrolysers currently use expensive catalysts and consume vast amounts of energy and water. It takes around nine litres of water to make one kilogram of hydrogen, plus there is a toxic output of chlorine.

“The biggest hurdle with using seawater is the chlorine, which can be produced as a byproduct,” says Dr Mahmood.

“If we were to meet the world’s hydrogen needs without solving this issue first, we’d produce 240 million tons of chlorine per year, which is three to four times what the world needs in chlorine.

“There’s no point replacing hydrogen made by fossil fuels with hydrogen production that could be damaging our environment in a different way.

“Our process not only omits carbon dioxide, but has no chlorine production.”

The research team utilised a special type of catalyst developed to work specifically with seawater, which Dr Mahmood says could significantly bring down the cost of electrolysers – enough to meet the Federal Government’s goal for green hydrogen production of $2 per kilogram, which would make it competitive with hydrogen sourced from fossil fuels.

“These new catalysts take very little energy to run and could be used at room temperature,” he says.

“While other experimental catalysts have been developed for seawater splitting, they are complex and hard to scale.”

This new method focuses on changing the internal chemistry of the catalysts, making them relatively easy to produce at large scale so they can be synthesised at industrial scale.

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