Climate rewind: Scientists turn carbon dioxide back into coal

Climate rewind: Scientists turn carbon dioxide back into coal
A schematic illustration showing how liquid metal is used as a catalyst for converting carbon dioxide into solid coal. Credit: RMIT University

Researchers have used liquid metals to turn carbon dioxide back into solid coal, in a world-first breakthrough that could transform our approach to carbon capture and storage.

The research team led by RMIT University in Melbourne, Australia, have developed a new technique that can efficiently convert CO2 from a gas into solid particles of carbon.

Published in the journal Nature Communications, the research offers an alternative pathway for safely and permanently removing the from our atmosphere.

Current technologies for and storage focus on compressing CO2 into a , transporting it to a suitable site and injecting it underground.

But implementation has been hampered by engineering challenges, issues around and about possible leaks from the storage sites.

RMIT researcher Dr. Torben Daeneke said converting CO2 into a solid could be a more sustainable approach.

"While we can't literally turn back time, turning carbon dioxide back into coal and burying it back in the ground is a bit like rewinding the emissions clock," Daeneke, an Australian Research Council DECRA Fellow, said.

"To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable.

"By using as a catalyst, we've shown it's possible to turn the gas back into carbon at room temperature, in a process that's efficient and scalable.

"While more research needs to be done, it's a crucial first step to delivering solid storage of carbon."

Scientists have used liquid metals to turn carbon dioxide back into solid coal, a breakthrough that could transform our approach to carbon capture and storage. Credit: RMIT University

How the carbon conversion works

Lead author, Dr. Dorna Esrafilzadeh, a Vice-Chancellor's Research Fellow in RMIT's School of Engineering, developed the electrochemical technique to capture and convert atmospheric CO2 to storable solid carbon.

To convert CO2, the researchers designed a liquid metal catalyst with specific surface properties that made it extremely efficient at conducting electricity while chemically activating the surface.

The is dissolved in a beaker filled with an electrolyte liquid and a small amount of the liquid metal, which is then charged with an electrical current.

The CO2 slowly converts into solid flakes of carbon, which are naturally detached from the liquid metal surface, allowing the continuous production of carbonaceous solid.

Esrafilzadeh said the carbon produced could also be used as an electrode.

"A side benefit of the process is that the carbon can hold electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles."

"The process also produces synthetic fuel as a by-product, which could also have industrial applications."

The research was conducted at RMIT's MicroNano Research Facility and the RMIT Microscopy and Microanalysis Facility, with lead investigator, Honorary RMIT and ARC Laureate Fellow, Professor Kourosh Kalantar-Zadeh (now UNSW).

The research is supported by the Australian Research Council Centre for Future Low-Energy Electronics Technologies (FLEET) and the ARC Centre of Excellence for Electromaterials Science (ACES).

The collaboration involved researchers from Germany (University of Munster), China (Nanjing University of Aeronautics and Astronautics), the US (North Carolina State University) and Australia (UNSW, University of Wollongong, Monash University, QUT).

The paper is published in Nature Communications ("Room temperature CO2 reduction to solid species on liquid metals featuring atomically thin ceria interfaces", DOI: 10.1038/s41467-019-08824-8).


Explore further

Improved understanding of groundbreaking liquid-metal 2-D technique

More information: Room temperature CO2 reduction to solid carbonspecies on liquid metals featuring atomically thin ceria interfaces, Nature Communications (2019). DOI: 10.1038/s41467-019-08824-8 , https://www.nature.com/articles/s41467-019-08824-8
Journal information: Nature Communications

Provided by RMIT University
Citation: Climate rewind: Scientists turn carbon dioxide back into coal (2019, February 26) retrieved 15 July 2019 from https://phys.org/news/2019-02-climate-rewind-scientists-carbon-dioxide.html
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Feb 26, 2019
I seriously doubt the viability of carbon capture, with or without conversion to artificial coal.

There is 2.8 tons of CO2 for every ton of high quality coal burned - and more total CO2 than all other human waste combined - and simple arithmetic tells us why CO2 capture is not going to be something that can save us from having to reduce emissions by fixing emissions after we make them. And I have to assume the energy requirements for turning CO2 into pure carbon exceeds the energy "gains" from burning the fossil fuels that makes it in the first place - so more clean energy is needed to do that than simply using it to displace the fossil fuel burning.

Feb 26, 2019
Ken environmental science is not based on numbers or EROI. It is based on hopes, wishes and magic catalysts.

Feb 26, 2019
@Ken
... assume the energy requirements for turning CO2 into pure carbon exceeds the energy "gains" from burning the fossil fuels that makes it in the first place - so more clean energy is needed to do that than simply using it to displace the fossil fuel burning.

Actually, from reading the Nature journal article (the whole thing is available at the link provided above) it seems that in the experimental setup at least it operates at a very low energy requirement. (They quote 75% conversion at -1.8 to -2.0V.) No doubt the power needs would scale with everything else but this process seems to be pretty efficient at first sight, and without much tuning attempted yet. It seems that it might be feasible to power this with solar photovoltaics. I agree with your sentiment that it's unlikely to be a quick and easy win though it might be part of the overall picture to help reduce the worst impacts of global warming. And it's quite cool that they can make some useful end-products.

Feb 26, 2019
Maybe someday I will hear that the warmer areas of Canada and Russia and the northern oceans are soaking up more carbon dioxide and are buffering the rise in green house gases.

Feb 27, 2019
& maybe not, Pa?

So, Coal Mining as an industry, is now on the list of obsolete & redundant liberally-expensive inefficient technologies.

Well, that's the way the wiseguys art the Wall Street Casino have been betting for the last decade.
Finding suckers to cash out their blue-chips to avoid all the fiduciary liabilities when all the mines are closed down.

Feb 27, 2019
Grandpa, the gain in carbon storage will be more than offset by the burning forest in Equatorial and Tropical Nations.

There is a limit to how far North, or South, we can go to mitigate the effects of overheating our planet. Best response is to turn down the heat some.

People forget that it is not just the increased CO2, but the excess energy it already released into the system AS heat is being retained unnaturally as well. Unnatural creation and then retention of that heat is more of a problem now tan it has been because there were not, previously in our histories, Billions of fossil fuel consuming autos and industries dumping heat into the system, even for local, inside cooling.

It has been well documented now for nearly 70 years, and going, with data being pushed farther and farther into the past with ice and lake sediment cores giving the history lessons we have not lived through.

Last time there was This Great of a change the world lost 70% of it's land-based life.

Feb 27, 2019
How stupid can u get with a university degree ?
And what will we do with this coal ?
I know ! we can bury it , then dig it up and burn it later !

Feb 27, 2019
Here is an idea. Just don't use coal.

Feb 27, 2019
Watch your six, hh3.
Some of the trumpesterfires blackshirt goons will show up to beat the crap out of you for uttering a sensible suggestion!

Say, do me a favor & let me know if under their fascist blouses? They are wearing horizontally-striped t-shirts?

After the re-education session? Be sure to thank them for the object lesson by saying:
"Спасибо тебе друг"
It;s only polite.
They will return your courtesy by replying "иди на хуй, если не можешь пошутить!"

Feb 28, 2019
I can turn co2 into carbon black with a TIG torch .

Mar 04, 2019
I seriously doubt the viability of carbon capture, with or without conversion to artificial coal.

There is 2.8 tons of CO2 for every ton of high quality coal burned - and more total CO2 than all other human waste combined - and simple arithmetic tells us why CO2 capture is not going to be something that can save us from having to reduce emissions by fixing emissions after we make them. And I have to assume the energy requirements for turning CO2 into pure carbon exceeds the energy "gains" from burning the fossil fuels that makes it in the first place - so more clean energy is needed to do that than simply using it to displace the fossil fuel burning.


how doesa ton of coal produce 2.8 tons of CO2.. I thpoght matter can't be created.

Mar 04, 2019
how doesa ton of coal produce 2.8 tons of CO2.. I thpoght matter can't be created.

You're forgetting that the C (carbon) in coal needs to combine with O2 (oxygen) from the atmosphere (so no matter created). C has an atomic weight of 12 and O2 has an atomic weight of 16. So 1 ton of pure carbon would produce 3.67 tons of CO2. But coal isn't pure carbon, so 1 ton of coal produces ~2.86 tons of CO2 (https://www.eia.g...tml#N_5_ ).

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