Science

Chemical reaction eats up CO2 to produce energy ... and other useful stuff

Chemical reaction eats up CO2 to produce energy ... and other useful stuff
Transmission electron microscopy image of carbon nitride created by the reaction of carbon dioxide and Li3N
Transmission electron microscopy image of carbon nitride created by the reaction of carbon dioxide and Li3N
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Transmission electron microscopy image of carbon nitride created by the reaction of carbon dioxide and Li3N
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Transmission electron microscopy image of carbon nitride created by the reaction of carbon dioxide and Li3N

While there are plenty of ways to make carbon-based products from CO2, these methods usually require a lot of energy because the CO2 molecules are so stable. If the energy comes from the burning of fossil fuels, then the net result will be more CO2 entering the atmosphere. Now a material scientist at Michigan Technological University has discovered a chemical reaction that not only soaks up CO2, but also produces useful chemicals along with significant amounts of energy.

Professor Yun Hang Hu and his research team developed a heat-releasing reaction between CO2 and lithium nitride (Li3N) - a compound that is the only stable alkali metal nitride and is made by reacting lithium with nitrogen at room temperature. Reacting lithium nitride with carbon dioxide resulted in 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 weren’t useful, but it is.”

In terms of energy release, when Hu’s team added CO2 to less than a gram of Li3N at 330° C (626° F), the surrounding temperature shot up almost immediately to 1,000° C (1,832° F) – which they point out is roughly the temperature of lava flowing from a volcano.

The research team’s work, which is funded by the National Science Foundation, is published in the Journal of Physical Chemistry.

Source: Michigan Tech

9 comments
9 comments
Astro Rosaire
Asinine, it takes much more energy to purify lithium salts into lithium metal. And then they react it with air... Does anyone else see how this is a bad idea?
Simon De Meulemeester
@Gwyn Rosaire: You remind me of Homer Simpson: "In this house, we obey the laws of thermodynamics!"
Joaquim Guerreiro
Useful for submarines and manned spacecraft. If you want to capture CO2 from the atmosphere you should stick with old school plant life.
Kradak
My own opinion is that nuclear offers nearly limitless power without CO2 emission. Convert this to Li3N and store it safely. Then, Li3N can be transported and deployed anywere you want, and in the long term, it can be used as a sink for CO2--unless you think that acidic oceans, thermally-driven local atmospheric distrubances, methane release from tundra, or the thermal expansion coefficient of seawater are a conspiracy, too.
usugo
if thermodynamics still apply to this world, producing Li3N probably cost much more energy than converting CO2 back to higher energy compounds. If not, then our problems are solved!
JoeReal
This brings a whole new meaning to effect of CO2 on ambient temperature. It used to be global warming, but when mixed with Li3N, and the temperature quickly soaring to that of molten lava, this is global cooking, :)
Currently, pure Li3N costs $6.35/gram....
Now, to find the cheapest way of making Li3N from lithium salt deposits...
Afterburner
Carbon nitride, aka hydrocyanic acid, aka cyanide, is a poison.
Lithium cyanamide, which is a poison, is a precursor to melamine, which is also a poison.
If cyanamides are used to create urea-based fertilizers by hydrolysis in acid solution (which is more easily achieved with ammonia and CO2), then you run into the issues of Ph impact of the soils, pollution of groundwater etc etc.
I don't see any good news here at all; headline should read: Scientist discovers expensive method to create poisons from harmless CO2!
Gerry Lavell
ChemSpider gives Lithium cyanamide as CH2LiN2.
Doug Hershberger
Wikipedia entry on Lithium Nitride has a small note saying "Main hazards reacts with water to release ammonia" - Somehow, to my feeble brain, that seems like a slightly dangerous from the only stable metal alkali. Perhaps the ratio of the metal to water has to be of such a level as immersion in water, but that still sounds like a potential recipe for disaster.