Water + Sunlight = Solar Hydrogen
by Jeremy Elton Jacquot, Los Angeles 
on 08.17.07
We've often heard the media and government officials talk up the potential for a future hydrogen economy to revolutionize the way we consume and produce energy. And while we've seen some promising applications of hydrogen as a fuel source in the last few months, it still seems very unlikely that we'll ever see a hydrogen-based energy market on the scale that some are envisioning. That's not to say that some scientists aren't still trying to gradually make this a reality: Craig Grimes, a professor of electrical engineering at Penn State University, has just announced that he and his team are close — in their words, "only a couple of problems away" — to developing a cheap, viable photoelectrolytic technology, that is one that would split water into hydrogen and oxygen by using sunlight.
While most current hydrogen production processes split hydrogen from natural gas — an inefficient technique that consumes energy and produces greenhouse gases — Grimes' method would rely on thin films made of titanium iron oxide nanotube arrays that could split water under natural light. According to Grimes, this method is much more eco-friendly since it only requires the natural energy of sunlight and doesn't produce GHGs.
The researchers already knew from previous trials that titanium oxide offered superior charge-transfer properties and corrosion stability, making it an ideal candidate for durable, inexpensive solar cells. Having used ultraviolet light to test earlier versions of their nanotubes — which only contains about 5% of the solar spectrum's energy — Grimes and his colleagues were keenly aware that they would need to find a way to harness a larger portion of the visible spectrum to make the nanotube arrays more efficient and viable.
Using a form of iron called hematite — a low band gap semiconductor material — they were able to capture a much larger portion of the solar spectrum in their arrays. In their recently published study, they reported a photoconversion rate of 1.5%, the second highest rate ever achieved using an iron oxide-related material.
They are now focusing on optimizing the nanotube architecture to obtain an efficiency closer to the theoretical maximum for materials with hematite (around 12.9%). Grimes is certainly hopeful about the prospects for his group's technology to transcend other production methods: "As I see it, we are a couple of problems away from having something that will revolutionize the field of hydrogen generation by use of solar energy."
Via ::Penn State Materials Research Institute: Revolution in Solar Hydrogen on the Horizon (press release)
See also: ::Trading Carbs for Hydrogen, ::Driving in Circles: Hydrogen Cars Close to Production at Ford
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How can you have a hydrogen "economy" when it's as freely available as sunshine?
The Sun is a big hydrogen fusion reactor. :-)
"How can you have a hydrogen "economy" when it's as freely available as sunshine?"
Feel free to manufacturer your own hydrogen extraction, storage, and utilization systems.
Other people will most likely wish to rent/purchase theirs.
That sort of thing an economy doth make....
I don't know the answers but out of personal interest I have a question. The idea is to recreate the natural effect of lightning in a closed system in order to induce electrolysis, and produce hydrogen.
What if we started with a closed system of water.
Then separated the system with a layer of glass
Then electroplated the the layer of glass with thin titanium oxide.
Then darken one side of the system so that the glass is dark, and completely resistent to light infiltration.
Then focused solar light energy on one side of the glass. LIke the childhood trick of starting a fire with a magnifying glass.
Now there is a temerature differential which would engage a natural force toward homeostasis
Would the resulting excitement of neutrons on the hot side create friction, resulting in static electric discharge, creating electrolysis effect sepatating the hydrogen from the oxygen?
Also what if the two sides of the water system were separated by an air gap which might conduct the static charge better?
"Would the resulting excitement of neutrons on the hot side create friction, resulting in static electric discharge, creating electrolysis effect separating the hydrogen from the oxygen?"
No. Neutrons do not excite, this is not a nuclear reaction, perhaps you mean neutral molecules? In any event, a thermal gradient does not produce electrolysis.
"Also what if the two sides of the water system were separated by an air gap which might conduct the static charge better?"
An air gap is an insulator, it doesn't conduct anything.
As a CPA and economics PhD, I feel there are a lot of misconceptions about what an 'economy' is. The term is thrown around a lot as if an economy is something tangible and disconnected from us. Nothing could be farther from reality. The economy is a concept, an aggregate of all the wants and demands of mankind. It works like this: let's say I have a bakery and in this bakery I make 2-pound loaves of bread. Most modern economists (i.e. the idiots employed by government, and politicians in general) would say that I am providing a supply of bread. This isn't inaccurate, but it's not the whole story. Ask yourself, why am I baking the bread? What do I seek to achieve? I expect to be paid, yes? Then it could also be said that my supply of bread to others reflects my demand for money (and by extension, other goods). Each and every one of us does this same thing in our work. We supply our time and labor because we demand the money we will be paid for it. Simply put, supply and demand are one in the same: two sides of the same coin.
As this relates to the "hydrogen economy," don't listen to any buffoon who claims that any resource is limitless. Hydrogen itself may be a practically inexhaustable source of fuel, but the capital equipment needed to transform and transport this commodity is not boundless. While some of you would jump at the idea of building your own hydrogen generator and would be able to do so, there are also many who cannot or wish not to spend their time building one. As a result, there would be a demand for generators, and the freer an economy is (that is, one with as few governmental regulations as possible) the more likely it is that an enterpreneur would arise to supply these generators. And if one businessman makes a great generator, like any other product, he might be, and should be, rewarded with a profit. These profits lure other enterpreneurs into the market for hydrogen generators and this competition produces a greater supply of generators, which means a lower cost to the consumer, and also creates an incentive for the enterpreneurs to invent more efficient generators to maintain their profits. Despite all the negative connotations the word has, a profit is an indication that someone has used resources efficiently.
Subsidies mess with this profit function and allow inefficient uses of resources to continue. Take ethanol, for example. It takes more energy to produce a gallon of ethanol from corn than burning the ethanol releases. In any free market, this enterprise would quickly die because people would use a more efficient energy source. However, when a politician steals money from you and me and gives it to the ethanol plant, the venture appears to turn a profit, although the reality is quite the opposite.
So in a hydrogen economy, there would be a demand for the equipment used to produce and harness the energy from this fuel. It would look very similar to the economy of today, except that the use of petroleum would be gradually replaced by hydrogen. As long as the cost of energy produced by hydrogen is less than the cost of energy produced by fossil fuels, one will be utilized over the other. Yet, since there is no limit to human demand for products, and therefore, no limit to the amount of energy a person might seek to employ for productive ends, oil will still be used, although it will be much less expensive due to the drop in consumer demand.