...a couple of problems away

The title up there is taken from a quote by Craig Grimes, a professor of electrical engineering at Penn State University.

According to Grimes, his group is “only a couple of problems away” from developing an inexpensive and easily scalable technique for water photoelectrolysis (the splitting of water into hydrogen and oxygen using light energy) that could help power the proposed hydrogen economy.

As you probably know, methods of hydrogen production currently employed split hydrogen from natural gas in a process that produces CO2, which is a climate changing greenhouse gas. Since hydrogen is abundently available in water (H2O) it would be much better--and cheaper--if we could extract it from water at a reasonable cost. You can do it now by running electrical current through water but it's not very efficient.

The Penn State scientists speculated that by doping a TiO2 (titanium oxide, a common ingredient in white paint) film with a form of iron called hematite, a low band gap semiconductor material, they could capture a much larger portion of the solar spectrum. Grimes was basing this on work done by Gopal K. Mor in which Mor described the fabrication of thin films made of self-aligned, vertically oriented titanium iron oxide (Ti-Fe-O) nanotube arrays that demonstrate the ability to split water under natural sunlight.

You gotta love this science stuff!

The Penn State research team is now looking into optimizing the nanotube architecture to overcome the low electron-hole mobility of iron. By reducing the wall thickness of the Ti-Fe-O nanotubes to correspond to the hole diffusion length of iron which is around 4nm, the researchers hope to reach an efficiency closer to the 12.9% theoretical maximum for materials with the band gap of hematite.

Titanium oxide has excellent charge-transfer properties and corrosion stability, making it a likely candidate for cheap and long lasting solar cells. However, as ultraviolet light contains only about 5% of the solar spectrum energy, the researchers needed to finds a means to move the materials band gap into the visible spectrum.

That's where the forementioned "couple of problems" comes up. Still, this is an amazing advance and could really do wonders for our energy needs in the near future. The bullshit about ethanol would go away in a minute (okay, make that a decade) if we could get hydrogen gas cheaply. And no pollution! In case you've forgotten your high school chemistry:

2 * H2 + O2 ===> 2 * H2O

2 molecules of hydrogen gas plus one molecule of oxygen gas combust to result in 2 molecules of water. An exothermic reaction. No fuss, no pollutants, just a bunch of heat results.

By the way, if you've always wanted a pet but don't have the room, The Grimes group has a dog on a microchip ...sorta.


rosemary said…
Damm Dave, I sure hope there isn't a test tomorrow because sure enough I have forgotten my high school chemistry. I'll study tonight maybe.
SassyAssy said…
hmm...if I can't get through your post without a nap, I don't know how I will pass this damn Biology clep on Friday!
Smug said…
Sorry - you lost me on this one! I really like the posts on things that I can relate to... like TV and movies - you know, the mindless stuff!!
Michael Manning said…
Utenzi: Yesterday I was griping about solar energy and why we haven't harnessed the sun's energy to better use. It's great to see you are passionate about a subject as important as our environment!
kenju said…
It's all Greek to me (except the titanium oxide)....LOL
tiff said…
Heat results? Global warming? Yes? or would the eventual dissipation of the carbon gasses that now trap heat in the atmosphere perhaps make up for the exotermic products of the combustion, maybe even resulting in stasis?

That would be awesome.

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