From MIT, a possible solution to allow coal fired power plants to meet the new draconian CO2 emission requirements imposed by the EPA. Hybrid copper-gold nanoparticles convert carbon dioxide to methane CO2=>CH4
May reduce greenhouse gas emissions
Various researchers around the world have studied copper’s potential as an energy-efficient means of recycling carbon dioxide emissions in powerplants: Instead of being released into the atmosphere, carbon dioxide would be circulated through a copper catalyst and turned into methane — which could then power the rest of the plant. Such a self-energizing system could vastly reduce greenhouse gas emissions from coal-fired and natural-gas-powered plants.
But copper is temperamental: easily oxidized, as when an old penny turns green. As a result, the metal is unstable, which can significantly slow its reaction with carbon dioxide and produce unwanted byproducts such as carbon monoxide and formic acid.
Now researchers at MIT have come up with a solution that may further reduce the energy needed for copper to convert carbon dioxide, while also making the metal much more stable.
The group has engineered tiny nanoparticles of copper mixed with gold, which is resistant to corrosion and oxidation. The researchers observed that just a touch of gold makes copper much more stable. In experiments, they coated electrodes with the hybrid nanoparticles and found that much less energy was needed for these engineered nanoparticles to react with carbon dioxide, compared to nanoparticles of pure copper.
A paper detailing the results will appear in the journal Chemical Communications; the research was funded by the National Science Foundation. Co-author Kimberly Hamad-Schifferli of MIT says the findings point to a potentially energy-efficient means of reducing carbon dioxide emissions from powerplants.
“You normally have to put a lot of energy into converting carbon dioxide into something useful,” says Hamad-Schifferli, an associate professor of mechanical engineering and biological engineering. “We demonstrated hybrid copper-gold nanoparticles are much more stable, and have the potential to lower the energy you need for the reaction.”
Going small
The team chose to engineer particles at the nanoscale in order to “get more bang for their buck,” Hamad-Schifferli says: The smaller the particles, the larger the surface area available for interaction with carbon dioxide molecules. “You could have more sites for the CO2 to come and stick down and get turned into something else,” she says.
Hamad-Schifferli worked with Yang Shao-Horn, the Gail E. Kendall Associate Professor of Mechanical Engineering at MIT, postdoc Zichuan Xu and Erica Lai ’14. The team settled on gold as a suitable metal to combine with copper mainly because of its known properties. (Researchers have previously combined gold and copper at much larger scales, noting that the combination prevented copper from oxidizing.)
To make the nanoparticles, Hamad-Schifferli and her colleagues mixed salts containing gold into a solution of copper salts. They heated the solution, creating nanoparticles that fused copper with gold. Xu then put the nanoparticles through a series of reactions, turning the solution into a powder that was used to coat a small electrode.
To test the nanoparticles’ reactivity, Xu placed the electrode in a beaker of solution and bubbled carbon dioxide into it. He applied a small voltage to the electrode, and measured the resulting current in the solution. The team reasoned that the resulting current would indicate how efficiently the nanoparticles were reacting with the gas: If CO2 molecules were reacting with sites on the electrode — and then releasing to allow other CO2 molecules to react with the same sites — the current would appear as a certain potential was reached, indicating regular “turnover.” If the molecules monopolized sites on the electrode, the reaction would slow down, delaying the appearance of the current at the same potential.
The team ultimately found that the potential applied to reach a steady current was much smaller for hybrid copper-gold nanoparticles than for pure copper and gold — an indication that the amount of energy required to run the reaction was much lower than that required when using nanoparticles made of pure copper.
Going forward, Hamad-Schifferli says she hopes to look more closely at the structure of the gold-copper nanoparticles to find an optimal configuration for converting carbon dioxide. So far, the team has demonstrated the effectiveness of nanoparticles composed of one-third gold and two-thirds copper, as well as two-thirds gold and one-third copper.
Hamad-Schifferli acknowledges that coating industrial-scale electrodes partly with gold can get expensive. However, she says, the energy savings and the reuse potential for such electrodes may balance the initial costs.
“It’s a tradeoff,” Hamad-Schifferli says. “Gold is obviously more expensive than copper. But if it helps you get a product that’s more attractive like methane instead of carbon dioxide, and at a lower energy consumption, then it may be worth it. If you could reuse it over and over again, and the durability is higher because of the gold, that’s a check in the plus column.”
Written by: Jennifer Chu, MIT News Office
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Where does the hydrogen come from ?
Easy, use coal and the water gas reaction to produce CO and H, combine the H with CO2 from
burned coal in the power plant and complete combustion of the CO generated in the water gas reaction to CO2 …. Uhh …. wait a minute
/sarc
It really is hard to believe that this got to the point of preparing an annoucement with no one asking some basic questions about where do the raw materials come from for the process in a real world application.
One thing to prove it is possible in the lab where you have a handy bottle of hydrogen to feed the reaction of CO2 to Methane and water with a catalyst and voltage input but ——- to put it mildly “WTF”
Larry
Ahhh.. but if you use solar energy to power the converter during the day…. you can use the CO2 over and over again.. and never release it into the atmosphere
Maybe..
Perhaps.
or not.
The question is whether the conversion of CO2 will be effective enough to keep the EPA off the backs of coal powerplants and be cheap enough that the coal powerplants can still compete with natural gas.
OK, so say they convert the CO2 to methane efficiently. When they burn the methane, don’t they get CO2 again?
Wow. If this stuff works, the greenhouse gas issue wouldn’t matter. That methane/methanol looks like low cost fuel to me. Who wouldn’t convert CO2 to fuel just for the economics of it.
@JuergenK re catalysts
A catalyst does not alter the energy requirement of a reaction; it alters the reaction rate, an entirely different thing. Also, the melting of bauxite is not a chemical reaction, it is a change of state. Adding cryolite creates an “alloy” with bauxite that melts at a lower temperature. There are plenty of such alloys in use (e.g., NaK). And, finally, until and unless the researchers compare the mass of methane generated to the joules of electrical energy used to create it, we will not know the process efficiency.
The implication of this discovery, however, is that one can take cheap nuclear energy, water, and carbon dioxide, and create literally limitless quantities of hydrocarbon fuels (methane can be polymerized into gasoline or kerosene). When the fuel is burned, we close the cycle back to CO2 and H2O and can start all over again. The total quantity of anthropogenic CO2 in the atmosphere cannot increase (as though that mattered). It could be an AGW nightmare.
See? that is the problem. That is not what catalysts do. Catalysts and enzymes reduce the free energy of activation for a certain reaction, meaning that the reaction goes at faster speed, but the energy needed for the transformation remains the same.
If you need 30 kcal to convert the reactants into products without catalysts, you still need 30 kcal with catalysts. That cannot change, it would be against the first law of thermodynamics. What changes is the barrier you have to jump to convert reactants into products. Catalysts reduce the barrier and thus, increase the reaction rate.
I can see how this scheme might work.
Generate one GW of electricity by burning coal.
Capture 25% of the stack CO2 emissions in a CO2 scrubber.
use 400 MW of electricity to generate hydrogen from water and create methane from the H and CO2.
Burn the methane in a “Green Energy Processor” (on site) generating 200 MW of electricity, let the CO2 escape the stack of the “GEP”.
Claim a 25% reduction in CO2 emissions for your “Clean Coal” plant.
Claim 200 MW of “Green Energy” from your “CEP”.
Dump 200 MW of efficiency to the atmosphere as waste heat with a net loss of 20% in the total process.
Sell the “Green Energy” at 300% markup (Subsidized).
Pay the EPA for your CO2 processing permit.
End global warming!
Besides, EPA is mainly trying to kill Big Coal, so they don’t want an efficient, cheap, scrubber technology even if it really worked. This would muddle their plans. In fact, if technical solutions to all our “pollution” problems magically appeared overnight, that would obviate the very need for an EPA, wouldn’t it?
Doesn’t even seem to be meant as April Fools joke, unless the whole MIT news office has fallen to one:
http://web.mit.edu/newsoffice/2012/hybrid-copper-gold-nanoparticles-convert-co2.html
Well, yes. They invented a catalyst that can convert CO2 into methane using electricity and some unspecified substance providing enough hydrogen for the reaction.That may be useful if you have lots of CO2 and that unspecified substance, an electric outlet, and need some methane for your laboratory burner. Or maybe someone somewhere will figure out some other good use for it. I just don’t see how could it ever reduce emissions any other way than formally (in the sense we store them here, then handle it over to someone else who takes care of releasing them).
I agree with a number of comments here – laws of thermodynamics seem to be ignored in this article, which is so skewed it is almost a propaganda piece, or an alchemy recepie – welcome back to the 16th century, folks.
To reduce CO2 one will need a reducing agent – H2. Which comes from another product of combustion – H2O, breaking up of which will require immense amounts of energy.
And why the hell anyone would want to reduce CO2 emissions anyhow??
FAIL
Catalytic converters on automobiles are also a “magic” gizmo. They convert complex, nasty hydrocarbon gasses and carbon monoxide into plant food and water. CO2 , of course, being the plant food.
From a non-chemist could it be (sorry don’t know how to do subscripts)
2 H2O + CO2 + Catalyst + pixiedust => CH4 + 2 O2 + Catalyst?
Which then becomes a perpetual motion machine as CH4 + 2O2 => CO2 + 2H2O + HEAT
“Which then becomes a perpetual motion machine as CH4 + 2O2 => CO2 + 2H2O + HEAT”
Except that the energy used to get the CH4 + 2O2 is greater than that released by its combustion.
This sounds like a neat physical chemistry experiment that was overheard by a bureaucrat who demanded they write up a press release explaining how it could be used to combat global warming.
What’s next. Something that reduces the entropy of the universe?? Having a PhD from MIT like I do, I am embaressed that somebody released this in this context. Interesting nanoparticle research and all, but as a way to turn CO2 into CH4 as a practical way to deal with CO2, never mind that dealing with it does not effect the climate, you gotta be kidding.
I thought they were going to make cows stop farting because Methane was worse?
Where will the energy come from to to make the conversion?
I think the collective “we” are out of our rabid-assed minds!
That is what we do when we plant trees and burn wood.
And that is really 100% natural.
Or, if you want, when we burn coal, release CO2, Plants eat CO2 and grow, they die, they get converted into coal and you have the longer cycle. That is ecology 101,
This is the wind gas story. To store the fluctuating wind power you need a CO2 source and a hydrogen source (electrolysis). With this catalyst you might reach 50% to 60% effeciency…
Better than fluctuating wind power, but even more expensive
This would be interesting if simply released as an innovative approach to stabilize the use of copper as a catalyst… even for the purposes of this particular reaction. In itself, this is probably legitimate research, and a respectable accomplishment. Nowadays, pure research is practically dead, and an unfortunate cycle that this truly exposes involves the use of unsubstantiated propaganda to latch on to the application that will drive the funding for continued research that may or may not be justified in itself. There seems to be a dillusion that marketing should drive technology even to the point of making claims never observed, nor particularly well founded.
” Instead of being released into the atmosphere, carbon dioxide would be circulated through a copper catalyst and turned into methane — which could then power the rest of the plant.”
This has to be a late April Fools joke. No one at MIT could be that damn dumb.
“Evil CO2” might be the main focus now, but “evil methane” is already in the background. The idiots are already looking at cows in a funny way. It will soon give way to “evil meat” and then we will be stuck with “evil vegetarians”. Oh wait, we already are…
Let us say that in your coal plant, you convert amount X of CO2 into methane. It cost you 1 kw/hr of power to do that. Then you burn the methane ( 25% efficient) and it produces amount Y of CO2. That gives you a net cost of 1000 watt/hr – 250 watt/hr =750 watt/hr to reduce your CO2 emmisions X – Y. THe question is is it worth it?
“You normally have to put a lot of energy into converting carbon dioxide into something useful,”
They don’t considering photosynthesis “something useful”?
No photosynthesis = No wheat/corn/rice/soy/vegetables/forage for animals = No meat
What do they expect people to eat? Some exotic stuff that depend on chemosynthesis?
Why not just go directly from coal to town gas and skip the CO2 generation ? It was all the rage when I was a boy. I still remember the gas spheres and filthy gas works.
Coal + water + high pressure = 50% hydrogen + 20% methane.
“Let us say that in your coal plant, you convert amount X of CO2 into methane. It cost you 1 kw/hr of power to do that. Then you burn the methane ( 25% efficient) and it produces amount Y of CO2. That gives you a net cost of 1000 watt/hr – 250 watt/hr =750 watt/hr to reduce your CO2 emmisions X – Y. THe question is is it worth it?”
Problem is, X-Y == 0.