New dyes improve solar technologies for generating clean electricity and hydrogen fuel

Dec 29, 2010

(PhysOrg.com) -- Chemists at the University at Buffalo have synthesized a new class of photosensitizing dyes that greatly increase the efficiency of light-driven systems that produce two kinds of green energy: Solar electricity and clean-burning hydrogen fuel.

On a commercial scale, these advancements could form the basis of cost-effective technologies to power everything from household appliances to vehicles.

To produce electricity, the dyes--called chalcogenorhodamine dyes--operate as part of a Grätzel-type solar cell that converts sunlight into an electric current. When sunlight strikes the , the energy knocks loose electrons in the dyes that travel through the solar cell, forming the current.

The mechanism for producing hydrogen begins the same way: Sunlight strikes the dyes, freeing electrons. But instead of forming a current, the electrons flow into a catalyst, where they drive a chemical reaction that splits water into its basic elements: hydrogen and oxygen.

In laboratory tests, scientists at UB and the University of Rochester have shown that these chalcogenorhodamine systems produce hydrogen at unprecedented rates, in part because the dyes absorb light more intensely and transfer their electrons more efficiently than conventional dyes.

The research team, led by UB Professor Michael Detty and University of Rochester Professor Richard Eisenberg, reported some of their findings in the Journal of the American Chemical Society in October 2010.

Detty, who worked in the private sector for 17 years before joining UB's faculty, hopes his research will lead to the development of better commercial technologies for producing and hydrogen on demand.

"Sunlight in one hour could power the world for a year, but we don't tap into it for either electricity or for making solar fuels," Detty said, explaining the importance of his work. "Plants use sunlight to make their own fuels. Humans don't. We use oil. So if we want to have energy independence, it will come from solar."

UB has received a Notice of Allowance from the U.S. Patent and Trademark Office approving the issue of a patent to cover the composition of the dyes. A separate patent application seeks to protect the dyes' use in hydrogen evolution and lists Detty and Eisenberg, along with Brandon Calitree, Alexandra Orchard and Theresa McCormick, as co-inventors of the process.

The collaborators found that chalcogenorhodamines work efficiently in homogenous hydrogen-production systems that employ cobalt as the catalyst, as well as in heterogeneous systems that employ platinum deposited on titanium dioxide as the catalyst.

Explore further: Research pinpoints role of 'helper' atoms in oxygen release

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User comments : 28

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wealthychef
5 / 5 (1) Dec 29, 2010
So bottom line me here, because it sounds like another "Yay, with this advancement, replacing oil with solar power is 10-15 years off." In other words, it never happens...
Glyndwr
4 / 5 (2) Dec 29, 2010
So bottom line me here, because it sounds like another "Yay, with this advancement, replacing oil with solar power is 10-15 years off." In other words, it never happens...


Small steps...are better than no steps
apex01
5 / 5 (1) Dec 29, 2010
I don't care about any sensationalism. All i care about is how much the efficiency supposedly improved.
Skepticus
3 / 5 (2) Dec 29, 2010
"...In laboratory tests, scientists at UB and the University of Rochester have shown that these chalcogenorhodamine systems produce hydrogen at unprecedented rates..."

Compared to what/which processes/technologies? 50 molecules of H2 and O2 in a million years instead of 100 million years?
Skepticus
Dec 29, 2010
This comment has been removed by a moderator.
Nemo
5 / 5 (3) Dec 29, 2010
Do a google search for Michael R. Detty . There's a little more info on his faculty home page.
Tangent2
2.3 / 5 (3) Dec 29, 2010
I don't care about any sensationalism. All i care about is how much the efficiency supposedly improved.


Same here. Where are the actual numbers that would support these outlandish statements?
Michael2010
4 / 5 (1) Dec 29, 2010
I don't care about any sensationalism. All i care about is how much the efficiency supposedly improved.


Same here. Where are the actual numbers that would support these outlandish statements?


Easy now. It's not that often that my alma mater and the city of my birth get mentioned in a positive light since we have the temerity to choose snow over hurricanes, mud slides, wild fires, tornadoes, earthquakes, hell fire, and the wrath of God.
logicali
5 / 5 (4) Dec 30, 2010
Cobalt and Platinum...

Whew! For a minute there I was getting worried that this would require rare and insanely expensive materials.
Sanescience
4.3 / 5 (3) Dec 30, 2010
"Sunlight in one hour could power the world for a year, but we don't tap into it for either electricity or for making solar fuels"...

Let's guess what would happen to the environment if all sunlight was blocked for an hour!

But in all seriousness, someday I can see environmentalists protesting solar collectors because they disrupt the natural convection currents of the planet.
antialias_physorg
5 / 5 (1) Dec 30, 2010
But in all seriousness, someday I can see environmentalists protesting solar collectors because they disrupt the natural convection currents of the planet.

Unlikely. If we gather enough energy for the world's needs (as stated in the article about an hour's worth every years) then that means that this is only 0.11% of what the earth receives.

Convection currents don't seem to be affected by the solar variation (which itself is about 0.1% of normal solar output)

Last but not least: all that 'captured' energy gets converted into heat along the line somewhere, anyways. So the net balance is zero.
GSwift7
1 / 5 (1) Dec 30, 2010
But in all seriousness, someday I can see environmentalists protesting solar collectors


They already protest solar collectors because of land and water use issues. One thing nobody talks about in regard to solar is that you are trapping sunlight and releasing it back out as heat when you use the energy.

Whew! For a minute there I was getting worried that this would require rare and insanely expensive materials


chalcogenorhodamine dyes aren't cheap or easy to synthesize either, never mind the catalysts. Then there's also the question of whether these dyes break down quickly in sunlight, like other organic dyes for solar energy. A dye that quickly fades in sunlight isn't much good for a solar panel.

Oh, and Rhodamine based dyes like this one are also toxic and water soluable. Not a good combo.
antialias_physorg
not rated yet Dec 30, 2010
One thing nobody talks about in regard to solar is that you are trapping sunlight and releasing it back out as heat when you use the energy.


Pop quiz: what do you think solar light gets converted to (whichever way it is used).

Answer: heat

They already protest solar collectors because of land and water use issues.

And mines (coal, uranium), oil rigs, refineries and conventional powerplants DON'T have land and water issues? o_O
GSwift7
1 / 5 (1) Dec 30, 2010
Oh good. Let's talk about physics.

MOST sunlight is reflected back into space. The reflected light is what you see when you look at things. MOST of the sunlight absorbed by the surface of the Earth is radiated back out to space as infrared radiation. A small portion of that is absorbed by water vapor in the air, and an even smaller portion of it is absorbed by other greenhouse gasses and converted to heat. You seem to be confusing heat with infrared radiation. Solar panels absorb more light than the Earth's surface normally would and then turns it into heat. It's a drop in the bucket, but could be significant if the solar panels become really efficient.

I didn't say that solar is worse than other types of energy in terms of land use. I simply stated that enviro-whackos file law suits to prevent solar plant construction just like they do any other type of power plant. To my knowledge, you can't build any type of power plant without getting law suits from somebody.
GSwift7
1 / 5 (1) Dec 30, 2010
Here's a question for you that I don't know the answer to: Are the groups who file those law suits funded by foreign interests? I mean really, why would anyone really want to block the construction of a solar plant? Does that make sense to anybody?
PPihkala
3 / 5 (2) Dec 31, 2010
I mean really, why would anyone really want to block the construction of a solar plant? Does that make sense to anybody?

Why are people opposing hydrogeneration? Because even if your generation does not have direct pollution like hydro or solar do not, they can still have adverse effects to the local environment they are situated. Hydro disturbs the flow of rivers, floods areas behind the dams and with solar there are other problems. Solar collectors shade the ground they are on and someone stated that solar collector areas must be controlled so that there is no vegetation shadowing the collectors. Therefore solar collector areas might be spread with plant killing agents to keep those plants out. And everybody knows how the local environment likes those substances... Then again collectors might need to be washed frequently to keep them clean and efficient. That means producing solar uses local water resources. Considering these, one can understand that solar is not all good.
antialias_physorg
5 / 5 (1) Dec 31, 2010
Solar panels absorb more light than the Earth's surface normally would and then turns it into heat.

Oh wow. And forrests absorb more light in summer than in winter. Then there is all the evil snow in winter that reflects a lot more than in summer. I think you need to get a grip on orders of magnitude here. Even if you plastered the entire US with solar panels then you'd have covered less than 2% of the globe (and plastering even something like an entire _state_ would be ludicrously large)

but could be significant if the solar panels become really efficient.

Efficiency has nothing to do with it. More efficient solar panels means less area needed.

To my knowledge, you can't build any type of power plant without getting law suits from somebody.

Only in the US. That's your problem.
Quantum_Conundrum
5 / 5 (1) Jan 02, 2011
Then again collectors might need to be washed frequently to keep them clean and efficient. That means producing solar uses local water resources. Considering these, one can understand that solar is not all good.


The best places to use Solar tend to be arid environments with little precipitation or clouds. You wouldn't use water in any case, you'd use a robot and a portable solar-powered air compressor to blow the dust off the panels.

Additionally, in real solar farms the panels tilt very much in early morning or late evening, so most dust and debris would fall off automatically due to gravity.

Alternatively, the robot could just use a soft duster or cloth.
GSwift7
1 / 5 (1) Jan 04, 2011
Even if you plastered the entire US with solar panels then you'd have covered less than 2% of the globe


I agree with what you say, and gave you 5/5. As I said in my comment, it's a drop in the bucket. However, when you start adding up the things humans do, you'll notice that urban heat islands have the ability to change local and regional climates. The solar plant alone may not be much, but it's a cumulative thing.

As for water use in solar plants, the process to make solar panels is water intensive and depending on the type of solar plant, some of them actively use water, like the ones that use steam to drive turbines. The average person doesn't have a clue about how much water can be used in a small to medium sized industrial facility. My medium sized plant makes about a million lbs of bread a week. 50-75% of dough weight is water, and about half of the water bakes out in the oven. Then we have to clean twice a week too. That's a lot of water.
antialias_physorg
not rated yet Jan 04, 2011
Again: You need to look at the sizes of these 'heat islands'. Humans have not changed the albedo of earth. Any energy that impacts on earth is reflected/converted into radiation of lower energies (i.g. heat) - which in turn gets emitted. It's much ore problematic to take _stored_ heat/energy and release it (oil, coal, gas, nuclear). This is a net addition to the energy balance. To convert energy that impacts on the earth anyways (by means of solar or , indirectly, wind energy farms) makes no difference in the energy balance at all.
antialias_physorg
not rated yet Jan 04, 2011
some of them actively use water, like the ones that use steam to drive turbines.

In closed cycles - just like any other powerplant (coal, gas, nuclear, ... ) on this planet. Power plants are not bakeries. If you observe conventional power plants you will still see plumes of water vapor emanating (not so with solar or wind). But even for these old power plants, that water vapor is not lost. It just goes back to the environment.

Cleaning of solar plants is also not a big issue (we have solar cells and a solar collector on the roof. Guess how often we have had to clean them in the past 10 years. )
In arid places I could imagine that abrasion by dust could be a problem. But basically all you'd have to do is wrap the collectors in cling-wrap and change that once a year. No cleaning, no abrasion.
GSwift7
1 / 5 (1) Jan 04, 2011
Try to google the following and click on the first thing that comes up. It's a Congressional Research Service report:

concentrated solar power water use

If you don't want to read the whole thing, then just read the second paragraph. The steam turbines are cooled with water, just like other steam turbine power plants. Water use is a significant issue for solar plants that use a steam turbine.

Right, cleaning solar panels or solar reflectors isn't an issue. That was someone else who said that. I just mentioned cleaning in regard to my place of work. totally off topic and unrelated to solar power. Just an example of how clueless most people are about water use. For example your complete lack of understanding in regard to the water problem for solar power. Sixty seconds of google time will cure your knowledge problem.
antialias_physorg
not rated yet Jan 04, 2011
The steam turbines are cooled with water, just like other steam turbine power plants.


Well, I've visited one or two solar power plants (and I've also visited coal and nuclear powerplants in the course of my engineering studies). Funny how there aren't any cooling towers at solar power plants. They're kinda hard to miss. (But the report you linked to makes a lot of sense on another level: The congress is basically all oil and energy barons)

Arid countries do manage to cool their generators somehow, you know? If they shift the energy production to solar the water 'problem' will get no bigger (much less in fact)

And are you saying that water use (even if it existed) with solar power plants would be a problem BECAUSE it uses less than any other type of power plant?
GSwift7
1 / 5 (1) Jan 05, 2011
Okay, if you don't like Congress as a good source, then how about the US Department of Energy. This is a peer-reviewed technical evaluation of the water use in various methods of cooling at concentrated solar plants. Your assumption that a big cooling tower like the ones at a nuclear plant are involved is faulty. As outlined in the following analysis, the absence of a cooling tower doesn't mean they aren't using water.

To find the report I'm talking about, go back and do the same google I suggested above, but choose the third thing that comes up.

There's a nice chart on page 17. As you'll see, solar is better than most (depending on the cooling method they use), but there's no free ride.
GSwift7
1 / 5 (1) Jan 05, 2011
lol, notice that for dish/engine solar collectors they actually list the water used for cleaning the mirrors: 20 gallons/megawatt hour. lol. Too bad dish/engine is so expensive to build and maintain.
antialias_physorg
not rated yet Jan 05, 2011
then how about the US Department of Energy.
Difference?

As outlined in the following analysis, the absence of a cooling tower doesn't mean they aren't using water.

The point is that if solar power plants used water anywhere near that of conventional power plants we'd see similar 'exhausts'. You can't hide that kind of water usage.

Then again: Solar is an _alternative_ source (meant to replace, not add to current power plants). So if anything the use of a solar plant will reduce the total water useage. (Using photovoltaics the water usage is nil, BTW. )
GSwift7
1 / 5 (1) Jan 05, 2011
Using photovoltaics the water usage is nil, BTW.


Okay then how about UC Berkley as a source (since they are about as leftist as you can get). Try to goole the following for an analysis of the cost/benefit of photvoltaics:

The Market Value and Cost of Solar Photovoltaic Electricity Production

This analysis has been done many times, by many people. Concentrated solar power from thermal is much better than PV. The scarcity of PV manufacturing materials will keep costs too high in all but the most extreme situations. Perhaps in places like Hawii or California, where electricity costs are way higher than other places, and sunlight is abundant, but not in most places. Even if they find a way to reduce the material use in the PV cells, an increase in demand would just keep the costs high regardless. The wiki page for PV taks about all of this. You should read about it. It's interesting.

antialias_physorg
not rated yet Jan 05, 2011
That paper is rather disputed

Google:

Estimates, Guesstimates, Obsolete Severin Borenstein
GSwift7
1 / 5 (1) Jan 06, 2011
lol, I was just looking at a web site for a company that designs and installs solar power for commercial use, such as installing on the roof of a factory. On the page where they describe the step by step process of the service they offer, there are a couple funny typos. Here's where they talk about how they help customers with government incentives:

Inventive Filing Assistance

Affordable Solar will assist the client in foiling for state and federal incentives, as well as any power purchase agreements available from the local utility


The company is Affordable Solar, and the page is their page on commercial applications and the how to get started tab of the page. That's just too funny. Do you think that the word inventive could maybe be a "mistake on purpose", kinda like when an envelope of money falls out of your pocket onto the judge's desk?