Current green hydrogen technologies use limited freshwater resources for electrolysis, as various ionic salts, particulates and microbes in sea water can interfere with the electrochemical water splitting. But this means 20 billion m3 of freshwater supplies will be required to meet the world’s future energy demands, placing up to 80% of the world’s human population at risk of water scarcity.

Green hydrogen generation via seawater electrolysis can be a sustainable approach, given the vast global resource available; so Suraj Loomba and his colleagues have been developing new, efficient, stable catalysts for splitting seawater into hydrogen and oxygen.

They used a hydrothermal method to prepare the transition metal oxide N-NiMoO3, which was further treated to create porous, ultrathin sheets to be used as a catalyst for the hydrogen evolution reaction (HER) in seawater. They also synthesised 2D sheets of WO3.B2O3 with an ionic bonded Co-MOF heterostructure as a catalyst for an oxygen evolution reaction (OER) in seawater. These two new catalysts replaced the processes currently limited to freshwater use, these being Pt/C and IrO2 respectively.

Suraj and his team found that the HER reaction performed twice as well as the freshwater Pt/C catalyst and 10 times better than the IrO2 when utilised as an anode to deliver current to the electrolysis process. The OER reaction also performed ten times better than IrO2. Importantly, the catalysts inhibited chlorine generation and corrosive chlorine chemistry, making them suitable for operation in alkaline seawater, capable of operating efficiently in a stable condition for months. At scale, the developed catalysts are reckoned to be around 50 to 60 times more economical than the current catalysts in commercial use.

Suraj Loomba is the Second Prize winner in the Physical Sciences Category of the Royal Society of Victoria's 2024 Young Scientists Research Prizes, sponsored by @ARPANSAGovernment and delivered as a part of the Inspiring Victoria program. He is completing his doctoral research at @rmit with supervisor Professor Nasir Mahmood.

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