(Ulm / Jena) – The universities of Ulm and Jena are researching the possibilities of converting sunlight directly into chemical energy. The “most important model is natural photosynthesis,” explain the scientists. With the development of “chemical solar energy converters”, green hydrogen could also be produced decentrally - for mobile, solar-powered hydrogen filling stations through to use in the climate-friendly electricity and heat supply of residential buildings.
Stabilize processes
One key is the optimization of catalysis materials and methods. “Previous systems for converting sunlight into chemical energy were relatively unstable: by embedding the light-driven catalyst molecules in 
“Soft matter, the consortium of chemistry, physics and materials science has succeeded in stabilizing and controlling this process,” says a statement from Ulm University.
Over the past four years, the research groups have developed, tested and linked molecular building blocks for solar energy conversion, explains Sven Rau, head of the Ulm Institute for Inorganic Chemistry I. “We were able to gain fundamental insights into the construction of light-driven catalysts in order to carry out highly efficient energy conversion “, said the professor. In addition, teaching materials on the subject of artificial photosynthesis have been designed and made available for chemistry lessons in high schools.
Funding for another four years
In order to advance research into the decentralized production of green hydrogen, the German Research Foundation (DFG) is now funding the project entitled “Light-driven molecular catalysts in hierarchically structured materials – synthesis and mechanistic studies” for another four years with more than twelve million euros.
In the second phase from July 2022, the scientists want to find, among other things, more readily available alternatives to the ecologically questionable and rare materials such as ruthenium, platinum or rhodium previously used in the catalysts or photo centers in order to make the solar energy converters more sustainable. The teams rely on organic dyes that are being researched in Jena.
They also want to “optimize the material connection”. The aim is a “light-driven process with coupled oxidation and reduction,” explains Benjamin Dietzek-Ivanšić from the University of Jena. The long-term goal is: “The production of artificial chloroplasts modeled on nature.” These plant cell components are responsible for photosynthesis.
ZSW joins in
The project is based on the special research area “CataLight“, under whose umbrella multidisciplinary teams continue to advance light-driven water splitting. The consortium includes the University of Ulm, the Friedrich Schiller University of Jena, the University of Vienna, the Max Planck Institute for Polymer Research and the Leibniz Institute for Photonic Technologies. In the future, the Center for Solar Energy and Hydrogen Research (ZSW ) as well as scientists from the USA.
Photo above
Research at the University of Ulm as part of the Transregio Collaborative Research Center CataLight © Uni Ulm / Elvira Eberhardt
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Catalysis solutions with luminescent ruthenium dye, which are irradiated with visible light in the “Azula” reactor. The model is photosynthesis in plants. © University of Ulm / Elvira Eberhardt
