Hydrogen is often described as a dream fuel for a cleaner future. When it is used, it produces only water, not carbon dioxide.
But turning that dream into reality has been difficult, especially when it comes to making hydrogen in a clean, affordable, and scalable way.
Now, researchers in Sweden say they have taken a major step forward by finding a way to produce solar hydrogen without using platinum—one of the world’s rarest and most expensive metals.
A research team led by scientists at Chalmers University of Technology has developed a new method that uses sunlight, water, and tiny particles of electrically conductive plastic.
Their findings were published in the journal Advanced Materials.
Traditionally, platinum has been used as a key ingredient, known as a co-catalyst, in systems that use sunlight to split water into hydrogen.
Platinum works very well, but it comes with serious problems.
Global supplies are limited, mining it can harm the environment and human health, and most production is concentrated in only a few countries, including South Africa and Russia. These issues make platinum-based hydrogen production expensive and hard to scale.
The Chalmers-led team, headed by Professor Ergang Wang, wanted to remove this bottleneck entirely. Instead of metal catalysts, they turned to a special kind of plastic known as a conjugated polymer. These materials are good at absorbing light and conducting electricity, but they usually do not mix well with water—an obvious problem when the goal is to split water molecules.
The breakthrough came from redesigning the material at the molecular level. By carefully adjusting the structure of the plastic, the researchers made it much more “water-friendly.” They also formed the material into extremely small particles, called nanoparticles. Inside these particles, the polymer chains are more loosely packed, which allows water and light to interact more effectively with the material.
“When people have tried to avoid platinum before, performance often dropped,” explained Chalmers researcher Alexandre Holmes, one of the study’s lead authors. “Here, we show that with smart material design, we can not only match platinum-based systems, but in some cases even outperform them—at a much lower cost.”
In the laboratory, the results are easy to see. When simulated sunlight shines on a beaker of water containing the plastic nanoparticles, tiny bubbles of hydrogen gas quickly begin to form and rise to the surface. The gas is collected through tubes, allowing researchers to measure production in real time. According to the team, just one gram of the plastic material can generate about 30 liters of hydrogen gas in one hour.
The advance does not stop there. Related work from other researchers at Chalmers has shown that this conductive plastic can also be produced without harmful chemicals and at much lower cost, making the overall process even more sustainable.
For now, the system still relies on vitamin C as a helper chemical to keep the reaction running smoothly. The next goal is even more ambitious: using only sunlight and water, with no added substances, to split water into both hydrogen and oxygen at the same time.
“Removing platinum is a crucial milestone,” Wang said. “Our next challenge is achieving fully sustainable water splitting. It will take more time, but we believe this approach puts us firmly on the right path.”
If successful, this technology could one day help make clean hydrogen a practical part of everyday energy systems—powered by sunlight, water, and a surprisingly versatile form of plastic.
