Researchers have developed a cheaper and more energy-efficient method of producing hydrogen directly from seawater, in an important step towards a truly viable green hydrogen industry.
A new method from researchers at RMIT University splits seawater directly into hydrogen and oxygen, skipping the need for desalination and its associated costs, energy consumption, and carbon emissions.
Hydrogen has long been touted as a clean future fuel and a potential solution to key energy challenges, especially for hard-to-decarbonize industries such as manufacturing, aviation and shipping.
Almost all of the world’s hydrogen now comes from fossil fuels, and its production emits about 830 million tonnes of carbon dioxide annually*. This is equivalent to the combined annual emissions of the UK and Indonesia.
However, emissions-free “green” hydrogen produced by splitting water is so expensive that it is almost commercially unviable, accounting for only 1% of total global hydrogen production. .
Dr. Nasir Mahmood, principal investigator and Vice Chancellor of RMIT, said green hydrogen production processes are costly and rely on fresh or demineralized water.
“We know that hydrogen has great potential as a clean energy source, especially for many industries that cannot easily switch to renewable electricity,” Mahmoud said. says.
“But to be truly sustainable, the hydrogen we use must be 100% carbon-free throughout its production lifecycle and not deplete the world’s precious freshwater reserves. yeah.
“Our method of producing hydrogen directly from seawater is simpler, more scalable and far more cost-effective than any green hydrogen approach currently on the market.
“With further development, we hope this can help establish a thriving green hydrogen industry in Australia.”
A provisional patent application for this new method has been filed and is described in detail in a laboratory-scale study published in the Wiley journal Small.
Separating the Difference: Seawater Catalysts
To make green hydrogen, an electrolyser is used to run an electric current through water, breaking it down into its constituent hydrogen and oxygen.
These electrolysers currently use expensive catalysts and consume large amounts of energy and water. It can take about 9 liters to make 1 kilogram of hydrogen. It also has toxic output. It’s chlorine, not carbon dioxide.
“The biggest hurdle to using seawater is the potential chlorine by-product. This is three to four times more chlorine than the world needs.It means replacing hydrogen produced by fossil fuels with hydrogen production that can otherwise damage the environment. No,” Mahmoud said.
“Not only do our processes save carbon dioxide, they also produce no chlorine.”
A new approach, devised by a team in RMIT’s multidisciplinary Materials for Clean Energy and Environment (MC2E) research group, uses a special type of catalyst developed specifically to work in seawater.
This research by PhD candidate Suraj Loomba focuses on the production of highly efficient and stable catalysts that can be manufactured in a cost-effective manner.
“These new catalysts require little energy to run and can be used at room temperature,” Mahmood said.
“Other experimental catalysts have been developed for seawater splitting, but they are complex and difficult to scale.
“Our approach focused on altering the internal chemistry of the catalyst in a straightforward manner, making it relatively easy to manufacture on a large scale and making it easy to synthesize on an industrial scale. ,” said Loomba.
Mahmoud said the technology promises to significantly reduce the cost of electrolysers. This is enough to enable the Australian government to achieve $2/kg of green hydrogen production, which is the Australian government’s target, and to compete with hydrogen produced from fossil fuels.
Researchers at RMIT are working with industry partners to develop aspects of this technology.
The next stage of research is the development of a prototype electrolyser that combines a series of catalysts to produce large amounts of hydrogen.
Original: How to make hydrogen directly from seawater – no desalination required
Than: Royal Melbourne Institute of Technology
