In the quest for the production of renewable and clean energy, photoelectrochemical cells (PECs) constitute a sort of a Holy Grail. PECs are devices able of splitting water molecules into hydrogen and oxygen in a single operation, thanks to solar radiation.
"As a matter of fact, we've already discovered this precious chalice, says Michael Grätzel, Director of the Laboratory of Photonics and Interfaces (LPI) at EPFL and inventor of dye-sensitized photoelectrochemical cells. Today we have just reached an important milestone on the path that will lead us forward to profitable industrial applications."
This week, Nature Materials is indeed publishing a groundbreaking article on the subject. EPFL researchers, working with Avner Rotschild from Technion (Israel), have managed to accurately characterize the iron oxide nanostructures to be used in order to produce hydrogen at the lowest possible cost. "The whole point of our approach is to use an exceptionally abundant, stable and cheap material: rust," adds Scott C. Warren, first author of the article.
At the end of last year, Kevin Sivula, one of the collaborators at the LPI laboratory, presented a prototype electrode based on the same principle. Its efficiency was such that gas bubbles emerged as soon as it was under a light stimulus. Without a doubt, the potential of such cheap electrodes was demonstrated, even if there was still room for improvement.
By using transmission electron microscopy (TEM) techniques, researchers were able to precisely characterize the movement of the electrons through the cauliflower-looking nanostructures forming the iron oxide particles, laid on electrodes during the manufacturing process. "These measures have helped us understand the reason why we get performance differences depending on the electrodes manufacturing process", says Grätzel.
By comparing several electrodes, whose manufacturing method is now mastered, scientists were able to identify the "champion" structure. A 10x10 cm prototype has been produced and its effectiveness is in line with expectations. The next step will be the development of the industrial process to large-scale manufacturing. A European funding and the Swiss federal government could provide support for this last part.
Evidently, the long-term goal is to produce hydrogen – the fuel of the future – in an environmentally friendly and especially competitive way. For Michael Grätzel, "current methods, in which a conventional photovoltaic cell is coupled to an electrolyzer for producing hydrogen, cost 15 € per kilo at their cheapest. We're aiming at a € 5 charge per kilo".
Michael Grätzel | EurekAlert!
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Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
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Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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