Polymer nanoparticles drive platinum free solar hydrogen

by Robert Schreiber
Gothenburg, Sweden (SPX) Jan 08, 2026

Hydrogen is seen as a central energy carrier in future low carbon systems because its use produces only water, but large scale deployment still depends on cleaner and more abundant production methods. A team led by Chalmers University of Technology in Sweden now reports a photocatalytic approach that generates hydrogen gas from water and sunlight without using the scarce and costly metal platinum, instead relying on tiny particles of electrically conductive plastic known as conjugated polymer nanoparticles.

The researchers describe how these polymer nanoparticles, when dispersed in water, absorb light and interact with their surroundings to drive hydrogen evolution. By tailoring the material properties at the molecular level, they improved the compatibility of the conjugated polymer with water, which is normally a limitation for this class of semiconducting plastics.

"Developing efficient photocatalysts without platinum has been a long-standing dream in this field. By applying advanced materials design to our conducting-plastic particles, we can produce hydrogen efficiently and sustainably without platinum - at radically lower cost, and with performance that can even surpass platinum-based systems", says Holmes, who together with Jingwen Pan from Jiefang Zhu's group at Uppsala University, is the joint first author of the paper.

The team reports that the key advance lies in the design of more hydrophilic, loosely packed polymer chains inside the nanoparticles, which enhances interactions with water and boosts the light to hydrogen conversion process. In a laboratory reactor at Chalmers, these particles generate visible streams of hydrogen bubbles under simulated sunlight, providing direct evidence of efficient photocatalysis.

When a lamp providing simulated solar radiation illuminates a beaker of water containing the nanoparticles, hydrogen bubbles form almost immediately and rise through the liquid before being collected and routed via tubing to a storage container, where the gas volume can be tracked in real time. With one gram of the polymer material, the system can produce about 30 liters of hydrogen per hour under these conditions, demonstrating a substantial production rate for a platinum free photocatalyst.

The work also builds on a separate advance from Chalmers colleagues showing that the same class of electrically conductive plastic can be synthesized without harmful chemicals and at lower cost, which further supports its use in scalable energy technologies. The researchers emphasize that removing platinum from the system addresses not only cost and resource constraints but also environmental and health risks associated with mining and refining the metal, whose production is concentrated in a small number of countries such as South Africa and Russia.

The next goal for the Chalmers team is to eliminate the need for sacrificial helper chemicals so that hydrogen production can rely only on sunlight and water. In the current experiments, vitamin C acts as a sacrificial antioxidant, donating electrons to prevent the reaction from stalling and allowing high hydrogen evolution rates in the lab, but it is not a sustainable input for large scale operation.

To achieve fully sustainable solar hydrogen, research leader Ergang Wang explains that the system must split water into hydrogen and oxygen simultaneously, with no additives other than water itself. "Removing the need for platinum in this system is an important step towards sustainable hydrogen production for society. Now we are starting to explore materials and strategies aimed at achieving overall water splitting without additives. That will need a few more years, but we believe we are on the right track", says research leader Ergang Wang, professor at the Department of Chemistry and Chemical Engineering at Chalmers.

The scientific article reports that the photocatalyst is based on low cost conjugated polymer nanoparticles and that its performance can match or exceed many existing platinum containing systems, while also benefiting from more benign synthesis routes. The study also notes that the work involved researchers from several institutions in Sweden, Brazil, China and the United States, and that funding came from the Swedish Research Council, Formas, the Swedish Energy Agency and the Wallenberg Foundations.

A background section of the release explains that electrically conductive plastics, or conjugated polymers, are organic semiconductors analogous to inorganic materials such as silicon and form the basis of organic electronics used in energy conversion, storage, wearable devices, electronic textiles and bioelectronics. The discovery that some plastics can conduct electricity dates back to the 1970s and led to the 2000 Nobel Prize in Chemistry for Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa.

Another background section outlines hydrogen's role as an energy carrier that can transport, store and supply energy, and that it can be produced from fossil, fossil free or renewable sources. Hydrogen is already used worldwide to store solar and wind energy, to help make homes energy self sufficient and as a transport fuel that does not emit harmful exhaust gases, which underlines why more sustainable production methods such as polymer based photocatalysis are being pursued.

Research Report:Highly Efficient Platinum-Free Photocatalytic Hydrogen Evolution From Low-cost Conjugated Polymer Nanoparticles