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
“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.
Is food not useful? Plants do that for free.
“LazyTeenager says:
April 12, 2012 at 5:57 am
Grant Shirreffs on April 11, 2012 at 2:16 pm said:
Doesn’t this sound suspiciously like a perpetual motion machine?
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Yep. While the chemistry is interesting the application as its described is bogus. You would need an external source of energy to run the reaction that converts CO2 to methane..”
No not at all perpetual because the article talks about producing methane from CO2 emissions from a coal fired power plant after the fuel is burnt. The power plant is your source of energy for the reaction.
To tell you the truth, this press release mystified me, because as 1) everyone else has pointed out, on the surface what is being reported is absurd, and 2) the author of the paper has real credentials as an engineer on the faculty at MIT. I will confess that I’m not quite sure what “biology engineering” is, even though I have two degrees in engineering (electrical and biomedical) and an MD to boot. But still, you would not think someone with the credentials the author had would produce a paper like this.
Last night as I was thinking about this, one thing occurred to me. . . . .is it possible that they somewhat are using the exhaust stack heat from the power plant to provide the predominant energy required for the CO2 ==> CH4 conversion, and that the electric power required for the reaction is relatively minimal? If I recall correctly, at least 50% of the energy produced from coal wounds up in the environment as heat.
If that is actually the case, this would be quite a breakthrough. Now having said that, I am still skeptical that it would “pencil out” at least on an energy efficiency/cost standpoint. I also don’t think strictly from a CO2 standpoint that power plants would be able to meet the proposed EPA requirements.
I’m hoping that what I’ve described is actually the case. . . .
The only remotely practical application I can think of for this, would be to use it as a form of chemical battery technology to convert excess wind generated power to a fuel that could be stored for a later use. Sort of the electrical to chemical equivalent of pumped storage. The question is would the infrastructure for such a use be cost effective given one of the required elements is gold and the the other is a highly useful raw material (copper) that has many other industrial uses.
Secondly could a electrical to chemical storage system accept the peak power needed to tame the intermittent nature of wind power. I suspect it would be a case of throwing more good money after bad by creating yet another boondoggle to try to fix the inherent problems of another poorly thought out boondoggle.
You would then have to build yet another layer of mostly idle infrastructure in the form of storage tanks and compressors for the generated methane and of course you need to have a natural gas fired generation plant handy to burn the methane when you tried to convert it back to electrical power.
Net gain as far as CO2 “elimination” would of course be not zero it would be less than zero as you would necessarily get back less power than the excess power you tried to store due to system ineffeciencies.
Larry
Well they start with a reaction that is not balanced, CO2=>CH4. And it goes downhill from there.
Gosh folks you are missing the big picture. I could purchase Green Electricity to convert CO2 into Green Methane. I could then take the Green Methane and feed it into a fuel cell to generate Green Electricity which I could sell to capture more Green Credits. Did I mention the fuel cell was Green which helps for more Green Credits? There is no doubt that the DOE would get a letter from the office of ‘Joe’ to provide funds for the construction of the plant to demonstrate the breathtaking technology, pronto. Think of all the green heading to my wallet!
Also, very exciting, is the new technology for improving gas mileage on cars by putting larger diameter wheels on the back so the car can run down hill. You can augment that with an exploding battery electric car that has a windmill on top to generate the electricity as you drive down the road.,
I am glad a lot of readers are picking up on the perpetual motion aspects of this idea. Just look at the simple themodynamics of the system. You start with coal that has a a high caloric value, burn it to produce CO2, a compound of a much lower caloric value. The energy relesed in the processed is used to make electrical power. Now to take the CO2 back to methane (CH4), a high caloric product nearly as energetic as coal, will require an input of energy that is more than what is relesed when you burned the coal! The catalyst only allows the conversion to methane to occur at a faster rate by lowering the activation energy of the reaction. Since the caloric value of coal and methane are about the same you have an energeticlly losing process. In addtion if H2 is required you need to make that which also cost you energy. This is energeticlly a non acceptable process. To make this work you need some cheap external sorce of energy. If we had that why would we bother burning the coal in the first place! The only efficient sorce for this power would be nuclear power. But if you had enough nuclear power plants to convert the CO2 back to CH4 why would be fooling around with coal in the first place!
Ben Wison says
“If I recall correctly, at least 50% of the energy produced from coal wounds up in the environment as heat.
If that is actually the case, this would be quite a breakthrough. Now having said that, I am still skeptical that it would “pencil out” at least on an energy efficiency/cost standpoint. I also don’t think strictly from a CO2 standpoint that power plants would be able to meet the proposed EPA requirements. ”
…….
Even if it is the case Ben, it still absolutely not a breakthrough in the slightest for improving efficiency and reducing CO2 emissions from power plants. The catalyst system requires electical energy to operate, not heat. Thus they have to convert the 50% waste heat to electricity to run the catalyst reaction. If they did that, they might as well just use that electrical energy they generate from the waste heat and pump it directly into the grid and bypass the CO2=>CH4 which is just an energy loss step. No matter how you slice and dice this…. you can only LOSE from an energy perspective.
This sounds like a perpetuum mobilae recipe. It will only work if the electricity used comes from another source, not from the burning of the coal or methane. So it could work as a way to convert windgenerated electricity plus flue gasses into liquid methane, for instance. Not very effective, I guess.
And folks, don’t worry about Methane. That number of 21 times more powerful etc .. comes from people who are completely clueless about the workings of radiation transport in the atmosphere. In fact the effects of Methane are miniscule compared with that of CO2 which in itself is already small. A complete red herring.
This is a great solution to EPA regulations. It reduces the CO2 and makes the power plant pass the new regulation requirements. You then sell the CH4 to another company that produces power under a different Title V permit. The EPA is happy, The coal fired power plant is happy and most of all, the customer buying electricty is happy. The way I see it, the only guy that is unhappy is the environmentalist and I really don’t care if he is unhappy. All this shows is that the new EPA regulations for coal fired power plants are stupid.
Obviously, you compress it and inject it into cattle. 😉
They don´t need any Gold. Nanocopper would readily oxidize if heated in a CO2 atmosphere:
CO2 + 2Cu = 2CuO (cupric oxide)
Nanocopper oxidizes easily in the air.
http://www.giurfa.com/ultranano.htm
Typo: It should read:
CO2 + 2Cu= 2CuO +Cº
Now that I thought about it, this technology would be GREAT for the future Green economy.
Run the coal-fired plants flat-out for solid baseload electrical energy, convert part of the emissions to methane (natural gas) and store on site as compressed natural gas (CNG) or maybe liquefied (LNG).
Then to cover peaks and the many frequent times when solar and wind flakes out, burn the methane in the gas turbine plant located right next to the coal-fired plant. All that’s needed is coal for dependable power as needed, and some water which could be recovered from the exhaust at both plants.
That’ll conserve all those many abundant reserves of cheap from-the-ground natural gas for heating and CNG-fueled vehicles, which will also drastically reduce our need for crude oil.
And the higher electricity prices will be offset by the increased use of the cheaper naturally-occurring natural gas for heating and transportation.
Yup, a win-win all the way around. Let’s do it!
(Or we could just admit the “Green economy” is a stupid concept all around, normal market forces have done quite well “greening” by rewarding increased efficiencies and reduced consumption. That’ll likely work better.)
You do NOT burn it at the plant. You sell it to someone else to burn. Not your problem then and your co2 burn rate in now within specs.
A reasonable solution to a bad regulation.
The paper is still in press, so it can’t have been published on April 1:
http://web.mit.edu/bio-nano/www/publications.html
Unfortunately, no working paper is linked.
John M Sez:
>They’re going to have trouble patenting this, since last I checked, the USPO still dismisses perpetual motion inventions out of hand.
Well, the USPTO might but I’m not sure about the US Post Office’s policy on PM.
🙂
Larry Ledwick: The only remotely practical application I can think of for this, would be to use it as a form of chemical battery technology to convert excess wind generated power to a fuel that could be stored for a later use.
I agree with that.
alcheson: Have to disagree, I think it would be as bad as I portray.
After thinking a while after I wrote my post, I decided that I agree with you. As you go on to say, it would be worse than you portray due to the inefficiencies of the intermediate steps. So, in short, I agree with you.
At best, it is one of a number of new catalysts for using surplus electricity (kind of a hypothetical construct, that surplus electricity) to make fuel for later use. Definitely not cheap now.
The MIT journalist, Jennifer Chu, can’t be Energy Secretary Stephen Chu’s daughter, since has only 2 sons: http://chineseculture.about.com/od/thechinesediaspora/p/Stevenchu.htm .
But still she might be related, perhaps a niece by one of his brothers.
Why not just run CO2 through a few greenhouses of genetically engineered plants designed to absorb more CO2 than normal and grow at a crazy rate? Then dry out the plants and burn them– voila! Reused CO2!
Now where’s my $1 million bucks, EPA?
Actually, this reaction might be very useful on nuclear submarines or spacecraft where the CO2 could be converted to methane, which could then be converted to ethanol in subsequent reactions. The Russians might want to employ such technology on the ISS instead of CO2 scrubbers, converting exhalation into vodka.
From Hu McCulloch on April 12, 2012 at 12:23 pm:
Thanks for clarifying that, since, you know, all those Chu’s look alike to us.
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/sarc
kadaka (KD Knoebel) says:
April 12, 2012 at 10:38 am
Now that I thought about it, this technology would be GREAT for the future Green economy.
Run the coal-fired plants flat-out for solid baseload electrical energy, convert part of the emissions to methane (natural gas) and store on site as compressed natural gas (CNG) or maybe liquefied (LNG).
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And the energy needed to compress the gas will come from where?
“Photosynthesis simply stated is 6CO2 + 6H2O + photons = C6H12O6 + 6O2”
The Gas of Life, by Dr. Jim Goodridge, http://wattsupwiththat.com/2012/02/29/the-gas-of-life/
[C6H12O6 is D-glucose, dextrose, grape sugar, blood sugar. Cells use it as the primary source of energy and as a metabolic intermediate]