Gothenburg, Sweden – Researchers at Chalmers University of Technology have developed a method to produce hydrogen gas efficiently using sunlight and water, without relying on the scarce and expensive metal platinum.

In laboratory reactors, bubbles of hydrogen gas can be seen forming with the naked eye, showing that photocatalysis is happening efficiently. The process uses tiny particles of electrically conductive plastic, known as conjugated polymers, which interact with sunlight and water to produce hydrogen sustainably and at low cost.

Professor Ergang Wang, leading the research team, said, “Removing the need for platinum in this system is an important step towards sustainable hydrogen production for society.” Joint first author Alexandre Holmes added, “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.”

The breakthrough came by making the plastic nanoparticles more water-compatible. Holmes explained, “We also developed a way to form the plastic into nanoparticles that can enhance the interactions with water and boost the light-to-hydrogen process. The improvement comes from more loosely packed, more hydrophilic polymer chains inside the particles.”

In the lab, one gram of the polymer can produce 30 litres of hydrogen in an hour. While vitamin C is currently used as a helper chemical, the team aims to achieve overall water splitting using only sunlight and water in the future.

The study, Highly Efficient Platinum-Free Photocatalytic Hydrogen Evolution From Low-cost Conjugated Polymer Nanoparticles, published in Advanced Materials, represents a major advance in affordable, sustainable hydrogen energy.

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