Direct O2 evolution in collisions of carbon dioxide with surfaces

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Giorgio
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Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby Giorgio » Thu May 30, 2019 8:53 am

This is off topic on fusion related news, but I stumbled upon it today and I found it ingenious and a proof that science can still surprise in areas one would not expect.

Long story short, they was trying to understand the presence of O2 into the CO2 tail of a comets and they though it might come from the comet CO2 impacting particles as it was ejected from the comet. So they shoot molecules of CO2 against a surface and the impact force bent the linear structure of the "O-C-O" molecule forcing some of them to split and release O2.
Clever, smart and new ideas for me, so I wanted to share with everyone.

Original news release:
https://www.caltech.edu/about/news/comet-inspires-chemistry-making-breathable-oxygen-mars


Nature's article with experimental details:
https://www.nature.com/articles/s41467-019-10342-6

If you don't have time to read all of it, you can skip directly to Fig.3 to get a sum up of the experimental results.
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Skipjack
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby Skipjack » Thu May 30, 2019 2:04 pm

How much energy does it take to do that compared to other methods of splitting CO2 into C and O2?

Aero
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby Aero » Thu May 30, 2019 4:49 pm

Does the character of the surface have any effect on the efficiency of oxygen production? I'm thinking along the lines of a catalyst. And there must be an energy level sweet spot to maximize conversion.
Aero

paperburn1
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby paperburn1 » Fri May 31, 2019 12:34 pm

Aero wrote:Does the character of the surface have any effect on the efficiency of oxygen production? I'm thinking along the lines of a catalyst. And there must be an energy level sweet spot to maximize conversion.



Ohhhh, I like where your headed with this idea.
I am not a nuclear physicist, but play one on the internet.

Giorgio
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby Giorgio » Fri May 31, 2019 5:18 pm

Skipjack wrote:How much energy does it take to do that compared to other methods of splitting CO2 into C and O2?


It's just a prototype, so I do not expect to have a meaningful efficiency right now if compared to other methods. I guess we will need to wait until they lay out some of the ideas they listed in the Discussion section of the paper:

"Finally, although the yield of O2 is relatively small in the current study, a combination of collisional activation with photoexcitation, electron attachment, and Eley–Rideal reactions in a plasma reactor may result in a process that could be promising for CO2 reduction strategies, as well as plasma-driven continuous O2 production in CO2 atmospheres. "
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Giorgio
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby Giorgio » Fri May 31, 2019 5:38 pm

Aero wrote:Does the character of the surface have any effect on the efficiency of oxygen production? I'm thinking along the lines of a catalyst. And there must be an energy level sweet spot to maximize conversion.


That's an interesting point about the catalyst idea.
The sweet spot for maximizing conversion in this experimental setup is listed in the paper as 56,4eV, see Fig.4 of the paper.
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hanelyp
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby hanelyp » Fri May 31, 2019 10:38 pm

How much does it erode the impacted surface? And I presume ambient pressure has to be very low, of the O2 is likely to quickly react with the released carbon.
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Giorgio
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Re: Direct O2 evolution in collisions of carbon dioxide with surfaces

Postby Giorgio » Sat Jun 01, 2019 10:11 am

hanelyp wrote:How much does it erode the impacted surface? And I presume ambient pressure has to be very low, of the O2 is likely to quickly react with the released carbon.


Quote from article:
"All experiments were carried out in a custom-made low-energy ion scattering apparatus34. The CO2+ ion beam was extracted from an inductively coupled plasma, struck in a reactor held at 2 mTorr using a CO2/Ar/Ne gas mixture supplied with 500 W RF power at 13.56 MHz. Ions were delivered to a grounded surface at 45° incidence angle; typical beam currents of 5–15 μA were spread over a ~3 mm spot. Beam energy was varied between 40 and 200 eV by externally adjusting the plasma potential. The beam energy distribution had a Gaussian shape with a FWHM of ~5 eV. "

For what I can read through the article, surface erosion is not a concern at the involved energies.


Also there is a nice animation of the discovered effect which I miss before:
https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-019-10342-6/MediaObjects/41467_2019_10342_MOESM4_ESM.mpg
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