Scientists have developed a new way to produce clean hydrogen using sunlight and liquid metal, offering a promising path toward greener energy made directly from seawater.
The method could help overcome long-standing challenges in hydrogen production and bring the world closer to a sustainable hydrogen economy.
Hydrogen has long been viewed as an ideal clean fuel. When used, it produces only water while delivering large amounts of energy.
This makes it attractive for powering transport, industry, agriculture, and even electricity generation.
The challenge has always been how to make hydrogen cleanly, cheaply, and at scale. Many current methods rely on purified water, expensive equipment, or energy-intensive processes, limiting their practicality.
The new approach, developed by a team of researchers in Australia, uses liquid gallium metal activated by sunlight to extract hydrogen directly from both freshwater and seawater.
The work was recently published in the journal Nature Communications.
Lead author and PhD candidate Luis Campos explained that the process relies only on light and readily available water sources.
“We now have a way of extracting sustainable hydrogen using seawater, which is easily accessible, while relying solely on light for green hydrogen production,” he said.
At the heart of the technology is gallium, a metal with a very low melting point. Gallium looks solid at room temperature but turns into a liquid just above body temperature.
This unusual property allows it to be used with relatively little energy input. The researchers also found that gallium particles can absorb light, which plays a key role in driving the chemical reaction.
In the process, tiny particles of liquid gallium are suspended in water and exposed to sunlight or artificial light. When light hits the gallium, it reacts at the surface with water molecules. This reaction releases hydrogen gas and forms a compound called gallium oxyhydroxide.
What makes the method especially appealing is that it is circular. After hydrogen is produced, the gallium oxyhydroxide can be converted back into gallium and reused again and again. This greatly reduces waste and lowers costs.
Senior researcher Professor Kourosh Kalantar-Zadeh said the results show how powerful liquid metals can be when their chemistry is carefully controlled. In early experiments, the team achieved hydrogen production efficiencies of up to 12.9 percent. While that may sound modest, Kalantar-Zadeh noted that early silicon solar cells started with efficiencies of around 6 percent in the 1950s and took decades to improve.
One major advantage of the new method is its ability to work with seawater. Many hydrogen production techniques require purified water, which is expensive and impractical in large quantities. By contrast, seawater is abundant and readily available, particularly for coastal regions.
Hydrogen researchers are excited because this approach avoids many of the obstacles faced by traditional “water splitting” methods such as electrolysis and photocatalysis. It does not require rare materials, high voltages, or complex infrastructure, and the gallium can be recycled within the system.
The research team is now working to improve efficiency and scale up the technology. Their next goal is to build a mid-sized reactor capable of producing larger amounts of hydrogen.
If successful, the approach could help make clean hydrogen a realistic option for powering parts of the global economy, using nothing more than sunlight, water, and a clever use of liquid metal chemistry.
