Making hydrogen straight from seawater without desalination
Ōtautahi - Researchers have developed a cheaper and more energy-efficient way to make hydrogen directly from seawater, in a critical step towards a truly viable green hydrogen industry.
The new method splits the seawater directly into hydrogen and oxygen skipping the need for desalination and its associated cost, energy consumption and carbon emissions.
The new method by RMIT University researchers in Melbourne splits the seawater directly into hydrogen and oxygen -- skipping the need for desalination and its associated cost, energy consumption and carbon emissions.
Hydrogen has long been touted as a clean future fuel and a potential solution to critical energy challenges, especially for industries that are harder to decarbonise like manufacturing, aviation and shipping.
Almost all the world's hydrogen currently comes from fossil fuels and its production is responsible for around 830 million tonnes of carbon dioxide a year, equivalent to the annual emissions of the United Kingdom and Indonesia combined.
But emissions-free green hydrogen, made by splitting water, is so expensive that it is largely commercially unviable and accounts for just one percent of total hydrogen production globally.
Lead researcher Dr Nasir Mahmood, a Vice-Chancellor's Senior Research Fellow at RMIT, said green hydrogen production processes were both costly and relied on fresh or desalinated water.
"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," Mahmood said.
"But to be truly sustainable, the hydrogen we use must be 100% carbon-free across the entire production life cycle and must not cut into the world's precious freshwater reserves.
"Our method to produce hydrogen straight from seawater is simple, scalable 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."
A provisional patent application has been filed for the new method, detailed in a lab-scale study published in Wiley journal, Small.
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 a lot of energy and water -- it can take about nine litres to make one kilogram of hydrogen. They also have a toxic output: not carbon dioxide, but chlorine.
The new approach devised by a team in the multidisciplinary Materials for Clean Energy and Environment (MC2E) research group at RMIT uses a special type of catalyst developed to work specifically with seawater.
Lisa was born in Auckland at the start of the 1970s, living in a small campsite community on the North Shore called Browns Bay. She spent a significant part of her life with her grandparents, often hanging out at the beaches. Lisa has many happy memories from those days at Browns Bay beach, where fish were plentiful on the point and the ocean was rich in seaweed. She played in the water for hours, going home totally “sun-kissed.” “An adorable time to grow up,” Lisa tells me.
Lisa enjoyed many sports; she was a keen tennis player and netballer, playing in the top teams for her age right up until the family moved to Wellington. Lisa was fifteen years old, which unfortunately marked the end of her sporting career. Local teams were well established in Wellington, and her attention was drawn elsewhere.