'Artificial Leaf' Concept Inspires Research Into Solar-Powered Fuel Production (phys.org) 40
Researchers from Rice University have created an efficient, low-cost device that splits water to produce hydrogen fuel. "The platform developed by the Brown School of Engineering lab of Rice materials scientist Jun Lou integrates catalytic electrodes and perovskite solar cells that, when triggered by sunlight, produce electricity," reports Phys.Org. "The current flows to the catalysts that turn water into hydrogen and oxygen, with a sunlight-to-hydrogen efficiency as high as 6.7%." From the report: This sort of catalysis isn't new, but the lab packaged a perovskite layer and the electrodes into a single module that, when dropped into water and placed in sunlight, produces hydrogen with no further input. The platform introduced by Lou, lead author and Rice postdoctoral fellow Jia Liang and their colleagues in the American Chemical Society journal ACS Nano is a self-sustaining producer of fuel that, they say, should be simple to produce in bulk.
"The concept is broadly similar to an artificial leaf," Lou said. "What we have is an integrated module that turns sunlight into electricity that drives an electrochemical reaction. It utilizes water and sunlight to get chemical fuels." Perovskites are crystals with cubelike lattices that are known to harvest light. The most efficient perovskite solar cells produced so far achieve an efficiency above 25%, but the materials are expensive and tend to be stressed by light, humidity and heat. "Jia has replaced the more expensive components, like platinum, in perovskite solar cells with alternatives like carbon," Lou said. "That lowers the entry barrier for commercial adoption. Integrated devices like this are promising because they create a system that is sustainable. This does not require any external power to keep the module running." The research has been published in the journal ACS Nano.
"The concept is broadly similar to an artificial leaf," Lou said. "What we have is an integrated module that turns sunlight into electricity that drives an electrochemical reaction. It utilizes water and sunlight to get chemical fuels." Perovskites are crystals with cubelike lattices that are known to harvest light. The most efficient perovskite solar cells produced so far achieve an efficiency above 25%, but the materials are expensive and tend to be stressed by light, humidity and heat. "Jia has replaced the more expensive components, like platinum, in perovskite solar cells with alternatives like carbon," Lou said. "That lowers the entry barrier for commercial adoption. Integrated devices like this are promising because they create a system that is sustainable. This does not require any external power to keep the module running." The research has been published in the journal ACS Nano.
Lifespan? (Score:2)
Re:Lifespan? (Score:5, Funny)
Who has a bridge for sale? (Score:1)
Re: Who has a bridge for sale? (Score:1)
You seem to confuse this aite with DashSlut - News for beauty salons, gossip that doesn't matter.
This used to be a a tech and IT news site for geeks. Note how the story fits right into that?
slowly getting there (Score:3, Interesting)
I don't know how many people remember 20 years ago when the science world decided global warming was real and we all got together and proposed creating "solar fuels."
There was a big effort with lots of people presenting at physics and engineering conferences for years on this to make sure enough people were on board. I'm a materials physicist and I remember thinking, "why are there talks on solar flux, the energy efficiency of RuBisCO, and the economic challenges of nuclear power at my conferences?" I think most scientific leaders had been planning on Al Gore winning the presidency, but nevertheless, the "Solar Fuel" people re-branded their work "Clean Coal" and got G.W. Bush to buy in. As far as the scientists behind it were concerned, it had very little to do with coal (other than a Republican was in office, and marketing is a thing).
Well, that didn't go so well.
Instead, the idea that global warming is a generally debatable issue arose, the scientists backing solar fuels ended up crippling their own idea by associating it with coal, a political divide was created between leading Republicans and leading scientists that has only broadened, and we ended up with a mixing pot of stuff that either we knew wouldn't technically work long term (biofuels) or ideas that we knew wouldn't economically work without an infrastructure investment in a chemical alternative to fossil fuels (carbon credits).
It turns out that Energy Density is important. Where we get energy is even more important. "Solar Fuel" is a great term because it combines efficient use of our one practical fusion reactor (the Sun) with implied high energy density storage. It might not happen tomorrow, but it's very likely this is key to long term renewable clean energy.
Re:slowly getting there (Score:4, Informative)
No, it wasn't. Ironically, they were saying that exact line then, too, which still wasn't accurate but was a fair bit closer.
The thing you're thinking about is from the mid-70s. You will note that the mid-70s was considerably longer ago than 20 years. And even then the scientific literature was definitely publishing more evidence of anthropogenic warming; popular media had some articles about cooling after a one-off bad winter.
I was actually about to comment on this guy about how the science world decided global warming was real long before that. I'm 36, I still have old files from earth day school projects about global warming from the 90s (generated on a Windows 3.1 machine). Me learning about it in school when I was a kid doesn't make it true, but it does make it more than 20 years ago.
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I don't know how many people remember 20 years ago when the science world decided global warming was real
20 years ago, it was global cooling and another ice age. 20 years from now, who knows what the scientists will be selling.
I remember talk of global cooling in the 1980s. By the time 2000 came around, people were already talking global warming.
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By the 70's and 80's the science around global warming was well established. At the time, the common term was "greenhouse effect". There was some flash-in-the-pan fad about cooling in the media after a single hyped-up article in Newsweek in 1975... So "talk", yes, but not in terms of where actual climate science was at.
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By the 70's and 80's the science around global warming was well established. At the time, the common term was "greenhouse effect". There was some flash-in-the-pan fad about cooling in the media after a single hyped-up article in Newsweek in 1975... So "talk", yes, but not in terms of where actual climate science was at.
I was born in the mid 1970s. My dad was a biologist and ecologist. My recollection of the early 1980s was talk of global cooling. By 1990 greenhouse effect or greenhouse gases were a concern. Again, we're talking trying to remember things from my early to mid childhood.
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hydrogen makes for a good battery. Even when efficiency is low, It transports over thousands of miles without any losses; unlike trying to move electricity via cables. It also directly correlates to our current designs on combustion based propulsion including gas turbine, jet turbines, internal combustion, as well as non-rotary forms of burning it for heat sources. Technically even fossil fuels are hydrogen fuel sources as they are hydrocarbons, and its not the carbon we seek to extract energy from. Without
Re: slowly getting there (Score:2)
All you say is true, but Hydrogen loves to mess up itâ(TM)s containers however, and who wants to deal with compressed gas. This leaf is a cool concept because we want to talk about a mobile chemical plant, powered by sun. There might be some options for producing H2 and maybe 02 in liquids, with some other elements added for when stability and ease of containment outweigh energy density concerns. Have to be clean burning of course.
Re: slowly getting there (Score:2)
Compressed bottles are a thing of the past. You should google all the fuel cell tech out there. How does this tech keep eluding /.? Its like a complete coverup here.
Hydrogen economy (Score:1)
hydrogen makes for a good battery.
Only if you ignore practical drawbacks. Like how it likes to diffuse through the walls of metal pipes, making them brittle. Or that a reasonable energy density requires compression to such a high pressure, that a good deal of energy efficiencies are lost. Never mind weight / cost / safety issues of such high pressure tanks. Or the extremely low temperatures needed if you want liquid hydrogen @ low pressure. About the only area where hydrogen shines, is in stored energy per weight. Which -in theory- could m
Re: Hydrogen economy (Score:2)
I don't think ammonia would survive the the PR blow of accidents with widespread use, we are accustomed to fire and explosions but the horror of big ammonia accidents is something else.
Just work it up to propane, ethanol or diesel instead.
Re: hydrogen (Score:1)
Comment removed (Score:4, Insightful)
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So that makes the total efficiency solar to wheels of an EV to be about 0.15 x 0.77 = 11.5% efficient
You're forgetting the part where the energy needs to be transported to the EV and needs to be kept in the form of electricity the entire way to prevent further losses.
The whole point of storing energy chemically is that it is generally easier to transport and store than electric charge, and that it has a higher energy density, not that it is more efficient.
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8 years in the making? (Score:1)
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if you are anywhere as old as I am (49) I was promised flying cars by the year 2000. Big fucking let down that one was :-)
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We have flying cars. They are just really noisy, expensive to buy and to run, and the risk of accident means they must be tightly regulated and only driven by specialist operators. If you're rich enough though, you can buy a helicopter.
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from what i have seen they are really driveable planes more than they are flyable cars. A flying car should really look like a car with some aerial features. Not a prop plane with its 20ft wings folded up.
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I was actually describing helicopters. That was the joke. We do have 'flying cars' - flying vehicles suitable for personal transportation - but the logistics of operating them just renders them unaffordable to the masses.
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noise would suck but if they could contain the rotors it would at least be a start. I have seen some pretty tiny 1 person copters. But you still need a 20x20 area where people are not standing to take off or land. One rotor mishap and its all over. Contained rotors using a quad copter concept at least would make that part safer. Noise would still be horrible.
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Plus there's the reliability issue. Imagine how many cars are on the road in a major city, and turn them all into helicopters. Now put ordinary people in control, who sometimes do stupid things. Car accidents are bad enough, but helicopters accidents on the same scale would be a lot worse.
Even if someone does produce the technology for flying cars, it's going to have to be rather dull. We certainly couldn't trust people to pilot the things on anything like a driving license - how would you ever keep them to
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That works for me. Autonomous shuttle/flight systems where you just push a button or two except in extremely rural areas where there probably isnt guidance control, like landing on a farm or big property.
Efficiency of 6.7%. (Score:3)
It's hard to say exactly how they're calculating that 6.7% number, but it's presumably taking the energy of the sunlight hitting it and comparing it against the energy value of the produced hydrogen. In a good area for solar you get about 4 hours per day at 1000 watts per square meter. So that would mean 6.7% of 4 kiloWatt hours per day, which is .268 kiloWatt hours (kiloWatt hours are a really stupid unit of measure, by the way). Over a year that would be 97.88164 kiloWatt hours. 1 gasoline gallon equivalent of hydrogen would be 33.4 kiloWatt hours, so that would be about 2.93 Gasoline Gallon Equivalents of Hydrogen. Comparing it to methane by energy content, to beat natural gas on the market you have to hit $0.23 per gasoline gallon equivalent or lower (the price of natural gas is actually lower than that right now, but it's an unsustainable price driven by the current oil price collapse). So, a single square meter of this artificial leaf could only sell its product for about $0.67 per year to be competitive. So, even if it's good for 30 years, the manufacturing cost, installation, land rental or amortized purchase price, hydrogen collection infrastructure and other overhead for 30 years would have to cost less than $20.21 to be competitive. In the meantime, the absolute cheapest price I can find for solar cells is something like $42.54 per square meter.
The article claims that this can be cheaply produced, but there's no real estimate of how much per square meter. As the above numbers show, it would be very difficult to be competitive with natural gas even if the panels were free to manufacture. This is ignoring all of the externalities that mask the real cost of natural gas of course, and it's assuming that the price of natural gas won't go up (at the moment, that's looking like a real possibility). Also, the efficiency of these cells may be able to go up a bit. The fact is that it's really hard to compete head to head with natural gas right now because it's crazy cheap.
If these cells could produce isooctane directly, at the same efficiency, the economics would change a bit. You could put that pretty much directly into gastanks. To beat gasoline you'd have to beat the price that it costs from the refinery. It's a bit hard to find exact numbers for that, but it seems to be about $1.25 per gasoline gallon for gasoline from oil to be competitive. So that's more than 5 times as much as natural gas. So that would be about $3.66 per year per square meter or about $109.87 for a 30 year period. It's conceivable that could be sustainable, but it would have to be a very cost-efficient operation. The hazardous, flammable materials spread over a wide area would also be an additional liability compared to just generating electricity.
All that said, I like the idea. It's just going to probably need a breakthrough jump in efficiency combined with the oil industry hitting a wall. The second one is a certainty in the long run, but it's hard to say how far out that is. Eventually, the extraction costs are going to get too high. Of course, by that point, other changes may make renewable fossil fuel substitutes like this as obsolete as the coal dust fueled internal combustion engine.
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According to this, 4 kw-hours per square meter isn't good, it's below average for the continental US. Good is 6 or 7.
https://www.solar-electric.com... [solar-electric.com]
Even so your point is taken, it's pretty shocking that a square meter would only produce about the equivalent of 5 gallons of gas per year in a good area.
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True, I'm underestimating a bit on available solar energy, but it looks like they're overstating their current efficiency, so it may even out. Interesting that industrial electrolysis seems to have an efficiency of up to 80%. So to match their best number you would just need to pump a bunch of solar panels with 8.375% efficiency. It's not too hard to get solar panels that have twice that efficiency. So current technology kind of makes this redundant. However, if they can make this significantly cheaper, or
High purity required? (Score:3)
There are important information that's missing here. How pure does the water need to be? How do the impurities get collected and how often do they need to be manually removed? Ideally, you don't want to siphon off part of the drinking water or have to build a large water filtration system. If it could run off rainwater, that would be awesome but that doesn't seem like something that would scale.
The ultimate question is: how much energy is going to be used to make the water used in this fuel production system?
... for when we murdered ALL the plants ... (Score:1)
Then we can drop this in the oceans, and steal the sunlight as there won't be any fish and plankton left either.
Before that, this is useless, as it will always take away that solar enegry from something else that's living, that we ultimately need too.
As opposed to solar power towers in the desert, and hydrogen/methane plants in deserts next to the ocean, which could not be more neutral, and are often even beneficial for nature.
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As opposed to solar power towers in the desert, and hydrogen/methane plants in deserts next to the ocean, which could not be more neutral, and are often even beneficial for nature.
Let's assume that solar power in the desert and next to oceans are beneficial to the environment. What is a nation supposed to do if they don't have access to deserts next to oceans? Or not enough area of this desert to meet their energy demands? There's a lot of nations like that. The entirety of Europe likely applies. As does smallish nations like Israel, Japan, and South Korea.
I guess these nations could import this energy from places that do have lots of sandy beaches next to the ocean. Places lik
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That plus a match (Score:2)