Skip to comments.From lemons to lemonade: Reaction uses carbon dioxide to make carbon-based semiconductor
Posted on 05/21/2012 3:30:16 AM PDT by LibWhacker
(Phys.org) -- A materials scientist at Michigan Technological University has discovered a chemical reaction that not only eats up the greenhouse gas carbon dioxide, it also creates something useful. And, by the way, it releases energy.
Making carbon-based products from CO2 is nothing new, but carbon dioxide molecules are so stable that those reactions usually take up a lot of energy. If that energy were to come from fossil fuels, over time the chemical reactions would ultimately result in more carbon dioxide entering the atmospheredefeating the purpose of a process that could otherwise help mitigate climate change.
Professor Yun Hang Hus research team developed a heat-releasing reaction between carbon dioxide and Li3N that forms two chemicals: amorphous carbon nitride (C3N4), a semiconductor; and lithium cyanamide (Li2CN2), a precursor to fertilizers.
The reaction converts CO2 to a solid material, said Hu. That would be good even if it werent useful, but it is.
And how much energy does it release? Plenty. Hus team added carbon dioxide to less than a gram of Li3N at 330 degrees Celsius, and the surrounding temperature jumped almost immediately to about 1,000 degrees Celsius, or 1,832 degrees Fahrenheit, about the temperature of lava exiting a volcano.
Hus work is funded by the National Science Foundation and detailed in the article Fast and Exothermic Reaction of CO2 and Li3N into CN-Containing Solid Materials, authored by Hu and graduate student Yan Huo and published in the Journal of Physical Chemistry.
I think this Michigan Technological University professor deserves the Nobel Prize...at the very least.
The publication is called "Phys Org" I presume the "Phys" comes from physics. How can an organization with physics in its name not even know the difference between energy and temperature?
Not so fast! Surely this is only of use if we can get out hands on lots of Li3N? Is there is a cheap easily available natural source?
It turns out, that carbon dioxide is one of the most useful compounds on any habitable planet throughout the Universe.
And this little dollop is just more frosting on the cake.
He gets his money from NSF and NSF gets it from Congress.
If you want to be a True Conservative and Real American then you should oppose this because it is Socialism.
Who ever said CO2 isn't useful? It makes soda and beer tolerable, and plants love it.
When used as a fertilizer, the cyanamide releases .... CO2.
So the fertilizer provides nitrogen for the soil and CO2 for the plants. Sounds like a win/win.
“get our hands on lots of Li3N”
You’re correct. Put another way, how much energy does it take to produce Li3N?
he means increasing energy input forces increased temp.
You’ve put you’re finger on it - Li3N is going to have to be prepared, and that’s going to cost not just money, but also energy.
So while the reaction of CO2 and LiN3 may be exothermic (heat-releasing), the overall reaction of (something) + ammonica (to give Li3N) + CO2 is probably not. And it’s not too tough to calculate what the overall energy balance would be - it all depends on what they react to get LiN3.
Kind of neat, but I wouldn’t start investing in CO2 futures quite yet.
Indeed. However, he said: "how much energy". He then gave the temperature in degrees. Temperature is NOT energy. The relation of energy to temperature is somewhat complex, including mass, specific heat, initial temperture, heat transfer rates due to conduction, convection, and radiation, and more.
Re: post 12 - every “LiN3” should = “Li3N”.
Damned chemical dyslexia!
By the way, Li3N will be very water sensitive, so much so that I expect it will react spontaneously with moisture in the atmosphere, which will further complicate any real use of this system.
Some just don’t have a sense of proportion. The implication is that somehow making computer chips out of CO2 will resolve, to any meaningful degree, the “global warming” problem - when the ratio of such useful use to problematic production is orders of magnitude of orders of magnitude. This isn’t “save the planet” material, it’s “Total Perspective Vortex” material.
Thanks LibWhacker. I didn’t check, this may have been posted before?
I’m not a EE so don’t try to pin me on this. But, from what I’ve read silicon based semiconductor technology is fast approaching it’s outer limit of performance capability. In other words, Moore’s Law my soon no longer be valid without a breakthrough. So, the industry is desperately searching for a new medium to replace silicon and take it to the next level. So far, it seems, no luck.
Lithium reacts with nitrogen to make Li3N. Refining the lithium, through electrolysis, is a VERY energy-intensive process.
The Laws of Thermodynamics:
0) You must play the game
1) You can’t win
2) You can’t break even
3) You can’t quit the game
Your question is the key to this. There is no free ride. If this reaction yields so much energy from highly stable CO2, Li3N is highly reactive and will react with almost anything it encounters. The energy released from the reaction must be first used to create the LiN3.
A bigger complication: you get Li3N by exposing Li to nitrogen. Refining lithium, however, consumes 35 kWh/kg. In comparison, burning one kg of coal produces just 2 kWh of heat energy (and much less than that in actual electrical output)
I reject the premise of the title that CO2 is “lemons”.
Very cool. But I still don’t get why people want to suffocate the plants.
This tech does seem pretty cool. It it is as good as it sounds, Al Gore and the other environmental pimps won't be happy because they really don't want solutions.
In my gut I suspect that the formation of lithium nitride requires a lot of energy, particularly if the starting material is elemental lithium. Production of elemental lithium is a highly energy intensive process.
Bingo! The answer as to why this will remain a laboratory curiosity -- at least as far as disposal of CO2 is concerned.
IF somone develops a semiconductor process/product based on the reaction product, a few Kg of CO2 might be sequestered by it. Qtherwise, it is a mere curiosity...
Of course, let me be the first to point out that there is ZERO need to "sequester" atmospheric CO2 in the first place...
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