Scientists Produce Cheap Hydrogen from Rust and Sunlight

Researchers at the Ecole Polytechnique Fédérale de Lausanne (EPFL) have managed to accurately characterize the iron oxide nanostructures to be used in producing hydrogen at the “lowest known possible cost”.

The news could make is possible to achieve the idea that water and some nano-structured iron oxide is all it takes to produce bubbles of solar hydrogen.  Photoelectrochemical cells (PECs) are devices able of splitting water molecules into hydrogen and oxygen in a single operation using only solar radiation.

The French are feeling pretty good.  Michael Grätzel, Director of the Laboratory of Photonics and Interfaces (LPI) at EPFL and inventor of dye-sensitized photoelectrochemical cells said, “As a matter of fact, we’ve already discovered this precious ‘chalice’. Today we have just reached an important milestone on the path that will lead us forward to profitable industrial applications.”

The peer-reviewed paper appeared this week in Nature Materials.  The standout point of the paper is they have managed to accurately characterize the iron oxide nanostructures to be used in a water splitting operation.

Scott C. Warren, first author of the article said, “The whole point of our approach is to use an exceptionally abundant, stable and cheap material: rust.”

The press release isn’t especially complete, but hints a major point of the groups progress may have been Kevin Sivula, one of the collaborators at the LPI laboratory, presenting a prototype electrode based on the same principle last year. Its efficiency was such that gas bubbles emerged as soon as it was under a light stimulus. That lit off realizing the potential of such cheap electrodes was demonstrated.  Still, there is still room for improvement.
 
The 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 by using transmission electron microscopy (TEM) techniques.

Grätzel explains, “These measures have helped us understand the reason why we get performance differences depending on the electrodes manufacturing process.”

Then comparing several electrodes, whose manufacturing method is now mastered, the scientists were able to identify the “champion” structure. A 10×10 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.

The long-term goal is to produce hydrogen in an environmentally friendly and especially, a competitive way. Grätzel said, “Current methods, in which a conventional photovoltaic cell is coupled to an electrolyzer for producing hydrogen, costs €15 per kilo at their cheapest. We’re aiming at a €5 charge per kilo.”

Source: http://actu.epfl.ch/