A low-cost way to make hydrogen from seawater has been discovered

Hydrogen is seen as an important clean fuel for industries that are hard to electrify directly, such as steelmaking, shipping and heavy trucking. Most hydrogen today is made using fossil fuels, or with large amounts of treated fresh water which is expensive and scarce in many parts of the world.

A team from the University of Sharjah says it has taken a step towards a novel solution. Their study, published in Chemical Communications, describes a new catalyst that can help make hydrogen directly from seawater which is in abundance on our planet. 

Green hydrogen is a clean fuel made by electrolysis, which uses electricity to split water into hydrogen and oxygen. Seawater is an obvious source, as it makes up around 97% of the planet’s water. But the salt in it causes problems during the process, such as corroding the metals that drive the reaction, and it can lead to toxic chlorine being produced in place of oxygen.

The new catalyst combines three ingredients: nickel hydroxide, cerium oxide and phosphate. All are abundant and relatively cheap, unlike the platinum or iridium used in many top-performing catalysts.

According to the researchers, it needs less energy to run, is better at producing the right reaction, and corrodes far less than versions without cerium oxide or phosphate. Its microscopic pyramid-shaped structure also gives it more surface area for the reaction to take place, speeding up the reaction.

In a stress test, the catalyst ran at high output for about 80 hours in simulated seawater without breaking down or losing performance.

If catalysts like this work reliably on seawater, hydrogen producers wouldn’t need to desalinate or purify water first, which would cut costs and reduce the demand on freshwater supplies. This is a particularly useful solution for industries by the coast, island nations and other places local to the sea but short of fresh water. As the process runs on renewable electricity, it doesn’t depend on fossil fuels - a critical step forward in light of global warming.

The researchers are clear that the product is in its early stages. Eighty hours is far short of what a commercial plant would need, and the tests used simulated seawater. As co-author Dr Tanveer Ul Haq puts it, it’s a meaningful early signal that the approach holds up in salty conditions.

The step from the lab to industry is a big one, but making hydrogen cheaper and more widely available is a challenge worth solving as we transition towards a greener future.