Researchers turn seawater into hydrogen with high efficiency

An international team led by University of Adelaide researchers has created green hydrogen from seawater by electrolysis without pre-treatment, using a non-precious and cheap catalyst, and claiming “nearly 100 per cent efficiency”.

The work was led by Professor Shizhang Qiao and Associate Professor Yao Zheng from the university’s School of Chemical Engineering, and the results published in Nature Energy.

According to a statement from University of Adelaide, they used seawater as a feedstock – without the need for pre-treatment such as “reverse osmosis desolation, purification, or alkalisation” – and a commercial electrolyser. 

“The performance of a commercial electrolyser with our catalysts running in seawater is close to the performance of platinum/iridium catalysts running in a feedstock of highly purified deionised water,” said Zheng.

Seawater is challenging to use as a hydrogen source, due to complications from corrosion and electrode side reactions in electrolysers.

“It is always necessary to treat impure water to a level of water purity for conventional electrolysers including desalination and deionisation, which increases the operation and maintenance cost of the processes,” added Zheng.

“Our work provides a solution to directly utilise seawater without pre-treatment systems and alkali addition, which shows similar performance as that of existing metal-based mature pure water electrolyser.”

The next steps involve scaling up with a larger electrolyser.