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Will man mimick nature to power the hydrogen economy?

Artificial photosynthesis and solar cells are just one of the exciting projects that Mallouk's teams are working on.  (Source: Penn State University)
A new research study has created a synthetic photosynthetic complex which has a net efficiency of 0.3 percent

Photosynthesis is the fundamental energy capture process which forms the foundation of all life on Earth.  On a most basic level, it involves using sunlight to split water molecules into hydrogen and oxygen and then using the hydrogen captured to fuel sugar production.   With hydrogen becoming more popular as a possible alternative fuel source, many researchers have yearned to duplicate this most basic of natural processes to allow for cheap, efficient hydrogen production.  They had little success -- until now.

In the past, natural and synthetic dye molecules which tried to split hydrogen and water were consumed during the reactions and did not provide a sustained reaction.  Worse yet, the chemical reactions were often from a net perspective endothermic; in other words they required energy instead of producing it.  Part of this is because of the ease with which oxygen and hydrogen recombine, and the fact that most of these investigated catalysts also catalyze the recombination, destroying your products.

Thomas Mallouk, a DuPont Professor of Materials Chemistry and Physics, and W. Justin Youngblood, postdoctoral fellow in chemistry, together with collaborators at Arizona State University succeeded where others have failed. The researchers developed a dye/catalyst system that mimics the oxidative and electron transfer processes of photosynthesis, ultimately producing hydrogen gas.  Their findings were presented at the meeting of the American Association for the Advancement of Science today in Boston.

Clusters of molecules using iridium oxide molecules as a center catalyst, surrounded by light absorbing orange-red dye molecules comprise the finished product.  The 2 nm complexes are roughly half dye and half catalyst in terms of diameter.  Orange-red dye was selected due to its extensive experimental record and its ability to absorb high energy blue wavelength light.

Water molecules bond to the complex, and when the complex absorbs sunlight, it splits them into hydrogen and oxygen.  Mallouk enthuses upon its near biological efficiency, stating, "Each surface iridium atom can cycle through the water oxidation reaction about 50 times per second.  That is about three orders of magnitude faster than the next best synthetic catalysts, and comparable to the turnover rate of Photosystem II in green plant photosynthesis."

The process needs a tiny bit of juice to get started.  The voltage required to split water is 1.23 V, and the system is almost at this power level.  By adding 0.3 V from titanium dioxide anode and platinum cathode electrodes, the water begins to split.  Separating the electrodes effectively reduces hydrogen/oxygen recombination.

The current process has a positive efficiency of about 0.3 percent.  This sounds pretty measly, but as Mallouk puts it, "Nature is only 1 to 3 percent efficient with photosynthesis.  Which is why you cannot expect the clippings from your lawn to power your house and your car. We would like not to have to use all the land area that is used for agriculture to get the energy we need from solar cells."

Mallouk hopes to eventually achieve efficiencies better than that of natural processes.  By changing the molecular geometry, he plans on upping the efficiency by better allowing light to be absorbed or by improving the bonding of water molecules to the surface of the complex.

Mallouk states optimistically, "This is a proof-of-concept system that is very inefficient. But ultimately, catalytic systems with 10 to 15 percent solar conversion efficiency might be achievable.  If this could be realized, water photolysis would provide a clean source of hydrogen fuel from water and sunlight."

The fact that the efficiency is anywhere near that of the Photosystem II protein complex, a marvel of biological design, is impressive in itself.  The fact that this system could be competitive one day with modern solar technology (currently around 10 percent efficient) and help to replace fossil fuels is even more impressive. 

With hydrogen fuel looking more and more promising, Mallouk and Youngblood's research is certainly a significant breakthrough. 



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RE: Quick! Patent it!
By Darkskypoet on 2/19/2008 10:47:50 PM , Rating: 2
Actually... It is not why we have generic drugs... We have generic drugs only because for those drugs the patents have expired. Other nations oft times have generic drugs because they don't obey developed world's patent law.

I understand the incentive of patents in so far as they grant a monopoly for a short time for the company in question to recoup R&D. However, Drugs, computer software, etc; are oft times bad examples of abuse for said 'patent benefits'. There are many patents that should be tossed (software / silly general ones), and many times I can't humanely fault the pre-patent expiration production of HIV/AIDS meds, et cetera in poorer nations.

But; to say that without a patent system in place that companies would fail to innovate isn't true either. For the first that did in a non patent world would dominate competition, forcing them into innovation. In fact, it would remove the ability to milk certain patents, resting on their laurels until its time to make the next cash cow.

The patent system / Intellectual property laws, favor the stronger more established companies / developed world; as they then hold more monopolies for extended periods of time. As well, it could be said that it thwarts a more wide spread innovation, allowing any firm to leapfrog off the knowledge gained (and used) by any other firm. In this scenario, the ability to utilize other once patentable tech to improve it now, not in x years, would allow a much quicker incremental advance in tech. As well, it would engage many developing countries (China / India / et cetera) in improving, rather then counterfeiting.

A better strategy, would be to reduce patent protection times, perhaps striking a balance between the protectionism inherent in the current system, and the outright corporate / industrial warfare in the the no patent scenario.

Drugs, for instance, are a good case for shortened patent times, as mot developed countries are aging rapidly and the reduced drug costs / greater availability of generic drugs would save quite a few health plans / consumers a ton of money.

Added to shortened patent (monopoly condition) could be a simple royalty system adding a cent or two per pill or some such payable to the developer. However, said developer could not refuse to 'license' said tech to any firm producing. In this way, R&D can be recouped, and greater volumes of product can get to those in need.

Wow, as I've typed so much here; long story short, IP /patent changes could be beneficial to all.


“Then they pop up and say ‘Hello, surprise! Give us your money or we will shut you down!' Screw them. Seriously, screw them. You can quote me on that.” -- Newegg Chief Legal Officer Lee Cheng referencing patent trolls














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