Champion nano-rust for producing solar hydrogen

Jul 07, 2013
Cross-sectional SEM images show 2L (a) and 6L (b) electrodes from a 45-deg. viewing angle. Credit: Nature Materials, DOI: 10.1038/nmat3684

EPFL and Technion researchers have figured out the "champion" nanostructures able to produce hydrogen in the most environmentally friendly and cheap manner, by simply using daylight.

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 into hydrogen and oxygen in a single operation, thanks to . "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 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 (TEM) techniques, researchers were able to precisely characterize the movement of the electrons through the cauliflower-looking nanostructures forming the 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 , 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".

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More information: Identifying champion nanostructures for solar water-splitting, Nature Materials, DOI: 10.1038/nmat3684

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djr
5 / 5 (1) Jul 07, 2013
5 euro per Kg still appears significantly higher than the current cost of hydrogen when produced using methane. It looks better - but seems we are still a long way from parity. Perhaps the distributed nature of this process may help the equation. It would be interesting to see a cost analysis of producing electricity using a fuel cell - run on hydrogen from this process. That would be cool - just add water - and run your home.

Here are some cost figures on hydrogen production from methane - http://www.hydrog..._gas.pdf
Aliensarethere
5 / 5 (1) Jul 08, 2013
You can drive about 100 km on 1 kg hydrogen. In Scandinavia you pay about 8 euro for 5 liters of gasoline, which should take you the mentioned 100 km. So it's cheaper if they can get down to 5 euro per kg, maybe I'm missing something?
grondilu
not rated yet Jul 08, 2013
remove this please

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