They produce green hydrogen directly from untreated seawater

31 Jan. () –

Researchers at the University of Adelaide, together with international partners, have successfully used untreated seawater to produce green hydrogen.

The team achieved this by introducing an acid layer over the catalysts in situ. “We have split natural seawater into oxygen and hydrogen with near 100% efficiency… using a cheap, non-precious catalyst in a commercial electrolyser,” said Shizhang Qiao, a professor at the University of Adelaide.

“We use sea water as raw material without the need for any pre-treatment process, such as reverse osmosis desalination, purification or alkalinization,” explained Associate Professor Yao Zheng, from the University of Adelaide’s School of Chemical Engineering. The team limited itself to filtering seawater, coming from the Huanghai Sea (China), to remove solids and microorganisms.

“The performance of a commercial electrolyzer with our catalysts in seawater is similar to that of platinum/iridium catalysts in highly purified deionized water,” Zheng added.

The researchers point out that the ocean is an “almost infinite resource”, representing 96.5% of the planet’s water reserves, but it has been difficult due to the complexity of the water profile.

The team’s solution boils down to adjusting the local reaction environment of the catalyst, which they did by introducing an acid layer on its surface that captured problematic ions and reduced the formation of solids that can block the electrode.

The team, made up of researchers from China’s Tianjin and Nankai Universities, and from Kent State in the US, along with those from the University of Adelaide, published their work in Nature Energy.

The method is most practical in regions with long coastlines and abundant sunlight, such as Australia, reports pv-magazine-australia.com.

The team will now work on expanding the system using a larger electrolyser so that It can be used in commercial processes such as the generation of hydrogen for fuel cells and the synthesis of ammonia.