It seems that it will be possible
to fabricate reliable photosynthetic material one atomic layer at a time using
industrial methods. The protocol been
worked on would drive hydrogen production which is intriguing. Such a system could well accept fairly low
yields if it is sufficiently cost effective.
Imagine a siding product that produces hydrogen as a byproduct. It does not have to be great to earn its
keep.
I suspect that such an end
product is still a fair ways away but it is certainly a decent objective and
producing hydrogen is a viable alternative to simple electric power for the
likely style of application.
A lot has been done in the past
few years to produce an energy absorbing and energy converting building
protocol. It appears that we are yet a
long ways away from a practical system, but the advantages are driving
interest. Thus the flow of incremental
improvements such as this.
New technique improves artificial photosynthesis
by Staff Writers
This discovery will make it possible to improve photoelectrochemical cells. In the same way that plants use photosynthesis to transform sunlight into energy, these cells use sunlight to drive chemicalreactions that ultimately produce hydrogen from water.
The process involves using a light-sensitive semi-conducting material
such as cuprous oxide to provide the current needed to fuel the reaction.
Although it is not expensive, the oxide is unstable if exposed to light in
water. Research by Adriana Paracchino and Elijah Thimsen, published in the
journal Nature Materials, demonstrates that this problem can be overcome by
covering the semiconductor with a thin film of atoms using the atomic layer deposition(ALD)
technique.
Under the supervision of Professor Michael Gratzel in EPFL's Laboratory
of Photonics and Interfaces, the two scientists achieved this remarkable feat
by combining techniques used at the industrial scale, and then applying them to
the problem of producing hydrogen. With their process, cuprous oxide can be
simply and effectively protected from contact with water, making it possible to
use it as a semiconductor.
The advantages are numerous: cuprous oxide is abundantly available and
inexpensive; the protective layer is completely impermeable, regardless of the
roughness of the surface; and the process can easily be scaled up for
industrial fabrication.
A promising technique
The research team developed the technique by "growing" layers of zinc oxide and titanium oxide, one atom-thick layer at a time, on the cuprous oxide surface. By using the ALD technique, they were able to control the thickness of the protective layer down to the precision of a single atom over the entire surface.
This level of precision guarantees the stability of the semiconductor
while preserving all of its hydrogen-producing efficiency. The next step in the
research will be to improve the electrical properties of the protective layer.
Using widely available materials and techniques that can be easily
scaled up brings the "green" photoelectrochemical production of
hydrogen closer to the industrial interest.
Source : Highly active oxide photocathode for photoelectrochemical
water reduction, Adriana Paracchino, Vincent Laporte, Kevin Sivula, Michael
Gratzel and Elijah Thimsen, Nature Materials, 8 mai 2011. DOI: 10.1038/NMAT3017
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