Researchers from the Department of Chemistry at the Royal Institute of Technology (KTH) in Stockholm, Sweden, have managed to construct a molecular catalyzer that can oxidize water to oxygen very rapidly. In fact, these KTH scientists are the first to reach speeds approximating those is nature's own photosynthesis. The research findings play a critical role for the future use of solar energy and other renewable energy sources.
Researchers all over the world, including the US, Japan, and the EU, have been working for more than 30 years on refining an artificial form of photosynthesis. The results have varied, but researchers had not yet succeeded in creating a sufficiently rapid solar-driven catalyzer for oxidizing water.
"Speed has been the main problem, the bottleneck, when it comes to creating perfect artificial photosynthesis," says Licheng Sun, professor of organic chemistry at KTH.
But now, together with research colleagues, he has imitated natural photosynthesis and created a record-fast molecular catalyzer. The speed with which natural photosynthesis occurs is about 100 to 400 turnovers per seconds. The KTH have now reached over 300 turnovers per seconds with their artificial photosynthesis.
"This is clearly a world record, and a breakthrough regarding a molecular catalyzer in artificial photosynthesis," says Licheng Sun.
The fact that the KTH researchers are now close to nature's own photosynthesis regarding speed opens up many new possibilities, especially for renewable energy sources.
"This speed makes it possible in the future to create large-scale facilities for producing hydrogen in the Sahara, where there's an abundance of sunshine. Or to attain much more efficient solar energy conversion to electricity, combining this with traditional solar cells, than is possible today," says Licheng Sun.
He points to the problem of skyrocketing gasoline prices, and these advances with the rapid molecular catalyzers can in turn lay the groundwork for many important changes. They make it possible to use sunlight to convert carbon dioxide into various fuels, such as methanol. And, technology can be created to convert solar energy directly into hydrogen. Licheng Sun adds that he and his research colleagues are working hard and pursing intensive research to make this technology reasonably inexpensive.
"I'm convinced that it will be possible in ten years to produce technology based on this type of research that is sufficiently cheap to compete with carbon-based fuels. This explains why Barack Obama is investing billions of dollars in this type of research," says Licheng Sun.
He has conducted research in this field for nearly twenty years, more than half of that time at KTH, and adds that he and many other researchers see efficient catalyzers for oxidation of water as key to solving the solar energy problem.
"When it comes to renewable energy sources, using the sun is one of the best ways to go," says Sun.
The research findings are of such importance that they have recently attracted the attention of the scientific journal Nature Chemistry.
The research pursued by Licheng Sun and his colleagues is funded by the Wallenberg Foundation and the Swedish Energy Agency. They collaborate with researchers at Uppsala University and Stockholm University, and, together with Professor Lars Kloo at KTH, they run a joint research center involving KTH and Dalian University of Technology (DUT) in China.
- Lele Duan, Fernando Bozoglian, Sukanta Mandal, Beverly Stewart, Timofei Privalov, Antoni Llobet, Licheng Sun. A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II. Nature Chemistry, 2012; DOI: 10.1038/nchem.1301
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