Skip to comments.Hybrid copper-gold nanoparticles convert CO2 (To Hydrocarbons!)
Posted on 04/11/2012 8:26:05 AM PDT by Red Badger
Copper -- the stuff of pennies and tea kettles -- is also one of the few metals that can turn carbon dioxide into hydrocarbon fuels with relatively little energy. When fashioned into an electrode and stimulated with voltage, copper acts as a strong catalyst, setting off an electrochemical reaction with carbon dioxide that reduces the greenhouse gas to methane or methanol.
Various researchers around the world have studied coppers 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.
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.
Its a tradeoff, Hamad-Schifferli says. Gold is obviously more expensive than copper. But if it helps you get a product thats 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, thats a check in the plus column.
This story is republished courtesy of MIT News (http://web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.
Researchers have combined gold nanoparticles (in light red) with copper nanoparticles (in light green) to form hybrid nanoparticles (dark red), which they turned into powder (foreground) to catalyze carbon dioxide reduction.
Cue McGyver - “The thing about hydrocarbons is...”
Actually, that would be Zinc.
Well, they have a copper jacket...............
How much voltage, for how long? IOW, will it cost more to supply the necessary voltage than the net value of the fuel produced?
Will it end up as inefficient as the other "green" technologies?
I guess I'm missing the point. Thermodynamics requires MORE energy to convert CO2 into methane than can be produced by converting (combustion of) methane back into CO2 and H2O. The total mass of carbon remains constant. So how does this help?
Wait a minute - they burn methane which produces carbon dioxide which they convert back into methane which they burn which produces carbon dioxide which they convert back into methane.....
When methane is burned the carbon turns back into CO2 so there is no net gain. Are they suggesting they've discovered a perpetual motion machine? Is there any point in doing this?
suck all the CO2 out of the air and then wonder why all the plants are ,ah, dead
This sounds really fishy to this old engineer, but I’m burdened with those old, crusty laws of thermodynamics that were formulated before the days of quantum physics and nanotechnology. Still, the prospect of oxidizing CH4 to form CO2 and H20 to release energy and then taking “relatively little energy” to convert CO2 to CH4 sounds more like a perpetual motion machine than an economically viable process.
I guess the point is the carbon never leaves the plant.?..........
The methane produced would not generate power for the grid, just the power to run the facilities at the plant..........
Sounds like another great money-wasting scheme to me. But it’s great for Professorette Chu, whose research is probably funded by Steven Chu (no relation?).
Meantime, they’re blocking the nuclear plants and shutting down the coal plants that would produce the needed electricity to do this.
Lights out! Time to freeze in the dark, while starving the plants.
Then the amount of energy to recycle more and more carbon will eventual overwhelm the productive capacity of the plant, consuming all energy converted from combustion of new carbon based fuels. Very strange.
Actually, you got the point. The author is counting on the 99% that read the article and never understand that point.
They hope you will flood the phone banks of your congress representative to fund this important research.
No different than the chasing of hydrogen fuel for the exact same reason.
The long term trend over millions of years is less and less CO2. We need more of it, not less.
Worse, there is some loss at each step.
Quick ~ somebody work this out ~ Coal + Air =, then we take the CO2 and convert that to Methane ~ then we burn that again. Remember to account for the additional O from the atmosphere.
There will be other byproducts that can be handled as solids.
The cost of the catalysts is probably far less than the costs of the lawyers!
Let’s see CO2 has one carbon atom and two oxygen atoms. Methane is CH4, that is one carbon atom and 4 hydrogen atoms. I never see in the article where the hydrogen atoms are going to come from. Besides as cheap as methane is today I don’t see the point.
I think you guys are missing something. It sounds to me like the whole article is talking about a breakthrough in combining CO2 and hydrogen, into methane. Thus its not a perpetual motion machine. The hydrogen will be supplied outside of this process. That is the only thing that make sense to me.
I wonder whether this science would work with other non-oxidizing metals like platinum or paladium and copper, as our catalytic converters already use these metals to reduce noxious gasses.
Perhaps the resulting methene could be recycled into the combustion process thru introducing it back into a turbocharger
Now if we can figure how to reverse the process we can turn coal into copper and gold.
“The hydrogen will be supplied outside of this process”
Of course hydrogen can be supplied at a cheap price. /s
Actually, this is really promising. It’s true that you need to add energy to convert the CO2 to hydrocarbons, but solar cells are certainly capable of providing the current necessary to facilitate the conversion. If this technology proves feasible, it would be a great step toward energy independence.
BTW, the oxygen to burn the hydrocarbons is simply recycled back to the atmosphere when the CO2 is converted to CH4.
This process also suggests a path to create natural gas inorganically in the earth’s crust: carbonate rocks, heat, and a little hydrogen could do the trick. The difficult part is creating the hydrogen efficiently.
Talk to Al Gore. He has been very successful turning coal into gold. I don't think he bothers with the coppers.
So we steam reform methane to make the hydrogen, to combine with CO2 with yet more energy consumption, to make methane?
This is feeding off the global warming scam of carbon capture, it is a net loss energy system.
The chemical reaction for combustion of methane is:
CH4 + 2 O2 → CO2 + 2 H2O (ΔH = −891 kJ/mol (at standard conditions))
Any reaction converting CO2 back into methane will consume 891 kJ/mol if 100% efficient. And no process is 100% efficient. So (and thermodynamics guarantees this result, hence no 'perpetual motion' machines) converting the same chemical reaction back and forth must ALWAYS result in a net energy LOSS. I'm a physicist, not a chemist, but this is pretty basic stuff.
The reaction took place in water. So I assume the water was the source of the hydrogen.
Maybe this could make coal-to-liquid more efficient? My understanding of the process is that it takes energy (in the form of heat) and CO2. Maybe this method could do the job using less energy?
Ultimately I think the goal of this research was to make it cheaper to reduce CO2 emissions, however it may be useful in other applications.
Thermodynamics should be required education for every citizen. Especially the morons in congress.
The process involves immesing the electrode in water through which CO2 is passed, so the current will break down the water molecules to obtain the hydrogen. The reaction produces 3 molecules of oxygen for each molecule of methane: 2H2O + CO2 = CH4 + 3O2
Then you need to add the energy required to separate the molecular bonds of water.
As an old engineer myself (ChemE), I must agree.
But this is a new age! The laws of thermodynamics, like the Constitution, are full of negative restrictions. We can just hopey-changey them to something else. ;D
My bad- the reaction is produces 2 oxygen molecules for each methane molecule:
4xH2O + 2xCO2 = 2xCH4 + 4xO2
There is no “free” energy, however if the technology is more efficient than existing processes to create synthetic hydrocarbons it could be useful.
“hydrocarbon fuels with relatively little energy”
Relative to what is the $64 question.
Copper — the stuff of pennies...
Actually, that would be Zinc.
Just goes to show you that researchers and writers know little about money.
Of course you wouldn’t use methane to produce hydrogen to be used to produce methane. One of the holy grails of catalytic chemistry has been efficient water splitting. That is the best place to find hydrogen for this process. And yes, it requires energy. My point was, simply, that if solar energy could create the current necessary to power this reaction, it would be an efficient way to produce a mobile fuel.
Of course, by trapping more solar energy, we could change the earth’s heat balance and create global warming.
(BTW, I am not a warmist, but I believe it is prudent to explore as many alternate energy processes as we can. It’s just good science.)
“Creativity is putting known facts together in new and unusual ways.”
You’re still ahead of me - everything I know about hydrocarbons I learned from watching McGyver. :-)
As for the Hydrogen, you would likely get it from water, but you need energy to separate it. You could get it from H2S, which is interesting because its a byproduct of hydrocarbon refining.
Either way, you have to add energy here to get the hydrogen. Question is whether you could generate enough using solar to make it work at scale.
The earth is producing all kinds of DC power everyday, just by having its metal core turning within the magnetosphere - 186,000 lightening strikes a day.
I saw a video of a refueling tanker manifesting ‘St. Elmo’s Fire’ and the fuel nozzle arc’ing and sparking against the jet its trying to refuel.
Consider they are likely using JP-4, which is pretty flammable and not JP-5, which you could use to put out a cigarette.
Lot’s of free electrical energy out there. It’s just a matter of putting lightning in a bottle, as it were.
But electrolysis of water is far more expensive than steam reforming methane. That makes a bad idea even worse.
This scam is not about energy production, it is about carbon nature. They may have improved the losses but it still operates at a loss.
Apart from recovering and recycling waste CO2, another angle to this process (if it is efficient enough) is that it could be another effective way to store and transport electric power. As methane, it transports nicely.
Isn’t thermodynamics the science that determines the size of showerheads and water reservoirs for toilets as developed by congresscritters?
Hmmm. I believe I’ve used copper to make ethanol too! :)
Will it end up as inefficient as the other "green" technologies?
Well, let's see...First you burn coal to make steam to turn a turbine that drives a generator that produces electricity. The process also produces CO2 which can be reacted with a copper/gold electrode in an undefined solution to produce methane (natural gas). So lets just burn the methane along with the coal, oh oh, we just produced more CO2...Back to the magic cells to make more methane.
At some point could we drop the coal altogether and just burn methane to produce electricity and CO2 while reacting the CO2 with the copper/gold electrodes and the secret sauce (with just a pinch of the electricity produced, leaving enough power to keep our customers smiling!) Let's look a little closer, we have a closed process with a fixed amount of CO2 which we convert to methane using a catalyst and electricity. We then burn the methane, extracting heat to produce electricity and more CO2 to continue the process indefinitely.
Neat! Except that the laws of physics regarding the conservation of energy require that the amount of energy needed to synthesize the methane will be greater than what you can recover by burning the same amount of as fuel. This is why all thermodynamic processes reject heat to the environment (cooling towers!!).
Lastly, converting all the CO2 produced by a coal fired power plant to methane or methanol does not destroy the gas forever, it hides it as unburnt hydrocarbons in the newly produced fuels. As soon as those fuels are burnt, presto, the same amount of CO2 is released into the environment, the energy recovered will be less then the energy input to the synthesis as electricity. And what a long strange trip it's been...
The closed box that produces perpetual energy output is just as imposable as the proverbial "free lunch".
Sounds like enough energy to keep the stack blowing eh!