Artificial photosynthesis advances with novel solar hydrogen technology

Artificial photosynthesis advances with novel solar hydrogen technology
by Riko Seibo
Tokyo, Japan (SPX) Dec 10, 2024

Professor Chiyoung Park and his team at the Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), have developed a cutting-edge solar hydrogen production system inspired by the natural process of photosynthesis. This innovation leverages supramolecular fluorophore nanocomposite fabrication to achieve sustainable energy production.

Collaborating with Professor Hyojung Cha of Kyungpook National University, the research focused on utilizing tannic acid-based metal-polyphenol polymers to enhance nanosurface adsorption. This approach enabled precise control over the self-assembly and optical properties of fluorescent dyes. The study uncovered key mechanisms of photoexcitation and electron transfer, leading to the creation of a biohydrogen production system powered by sunlight and bacterial hydrogenase enzymes.

Natural photosynthesis relies on chlorophyll to absorb light energy and facilitate electron transfer, converting light into chemical energy. Mimicking this process, the team developed a supramolecular photocatalyst by modifying rhodamine dyes into amphiphilic structures. By incorporating tannic acid-based metal-polyphenol nano-coating technology, the team improved both the performance and durability of the catalyst. Under visible light, this system achieved a hydrogen production rate of approximately 18.4 mmol per hour per gram of catalyst - 5.6 times higher than prior studies using similar materials.

To further enhance the system, the team integrated the supramolecular dye with Shewanella oneidensis MR-1, a bacterium capable of electron transfer. This bio-composite system converted ascorbic acid (vitamin C) into hydrogen, showcasing stable and continuous hydrogen production over extended periods.

"This study marks an important achievement that reveals the specific mechanisms of organic dyes and artificial photosynthesis," said Professor Park. "In the future, I would like to conduct follow-up research on new supramolecular chemistry-based systems by combining functional microorganisms and new materials."

The research, led by first author Seokhyung Bu, a PhD student, was supported by the National Research Foundation of Korea and the Ministry of Trade, Industry and Energy under the Alchemist Project. The findings were published in Angewandte Chemie International Edition.

Research Report:Supramolecular Reconstruction of Self-Assembling Photosensitizers for Enhanced Photocatalytic Hydrogen Evolution