Electrode technology helps produce hydrogen fuel from seawater

Because the salt in seawater is corrosive and this would cause the production process to produce toxic chlorine gas, but new electrode technology can separate clean hydrogen fuel from seawater without filtering or pre-treatment .

This technology marks a major step forward in the commercialization of hydrogen as a sustainable energy solution.

'Traditional electrolysis can only be performed with pure water, an increasingly scarce resource ,' Doug Wicks of the US Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) said in a press release. 'We no longer have to rely on pure water, but instead rely on the most abundant water resource: the ocean.'

Seawater could become a source of clean hydrogen fuel. (Photo: Tamara Kulikova/Alamy)

The process uses a negatively charged cathode and a positively charged anode to separate seawater into four 'streams' – oxygen, hydrogen, harmless acids and alkalis. The alkali stream reacts with atmospheric CO2 _to form stable minerals that are returned to the sea, while the acid stream returns to the ocean after being restored to its original pH by flowing through silica-rich rocks.

Electrolysis of seawater not only produces hydrogen and oxygen, but also chlorine gas (Cl₂), a toxic substance, due to the presence of chloride ions (Cl⁻) in seawater. This process can corrode the electrodes and quickly damage the electrolyzer. Based on laboratory testing, Chen and his colleagues predict that these anodes could operate continuously for about three years before requiring maintenance, which involves removing them to reapply the chlorine-blocking coating.

Pau Farras, a scientist at the University of Galway in Ireland, commented that the three-year performance of the oxygen-selective anodes was impressive. He agreed that it was a promising method for using seawater to produce hydrogen fuel . However, Farras stressed that while the lab results were promising, it remains to be seen whether these anodes can maintain similar performance when operating in the natural environment.

The company is developing oxygen-selective anodes that will soon begin mass production at a plant in California, with an expected capacity of around 4,000 anodes per year. The project promises remarkable results, with the ability to remove 10 tonnes of CO₂ and produce 300 kg of hydrogen per day.