Solar fuel breakthrough may unlock cheaper green energy

Solar fuel breakthrough may unlock cheaper green energy
by Robert Schreiber
Berlin, Germany (SPX) Sep 25, 2025

Researchers at Lund University have taken a major step toward solving one of the biggest obstacles in developing efficient solar fuels. Their work shows how inexpensive iron-based systems could be used more effectively to store solar energy as fuel, paving the way for cheaper and more sustainable alternatives to fossil fuels.

Producing fuels such as green hydrogen requires catalysts that can capture solar energy and transfer electrical charges to acceptor molecules. Iron, an abundant and environmentally friendly metal, has long been considered a promising candidate. Yet its systems have struggled with energy losses that make them far less efficient than costly rare earth-based alternatives.

The Lund team used advanced simulations to probe the problem at the molecular level. They found that energy often dissipates because acceptor molecules stick to catalysts before charge transfer is complete. Crucially, their analysis revealed hidden mechanisms where nearby molecules assist in passing along the charge, greatly improving efficiency.

"We can now see previously hidden mechanisms that would allow iron-based molecules to transfer charge more efficiently to acceptor molecules. This could effectively remove one of the biggest obstacles to producing solar fuels using common metals," explained chemistry researcher Petter Persson.

The findings suggest that molecular surroundings play a more important role than expected. "It was surprising that the surroundings play such a crucial role. Our simulations show several unexpected ways in which the interaction with neighbouring molecules can facilitate the formation of energy-rich products," Persson noted.

While this advance addresses the vital first step of charge separation, more progress is needed before iron-based solar systems can reliably generate finished fuels. Still, the study offers new design insights that could accelerate development of efficient solar-to-fuel conversion using abundant materials.

"The study provides new insights into how solar energy can be converted more efficiently using common metals such as iron. In the long run, this can contribute to the development of cheaper and more sustainable solar fuels - an important piece of the puzzle in the global energy transition," Persson concluded.

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